Here is a quick example with memorizing Japanese vocabulary for those who are interested.
I have a bedroom in my apartment that I can picture very quickly and easily. I won't reveal its entire layout, but suffice it to say that upon walking into the room, to my right, there is a trash can, and a big bed is right in the middle of the room facing a window. Also, to the right of my bed is a table. Now, you also have to possess some relatively good imagination skills. Let's assume that it is very cold in my apartment. In fact, so cold so as to cause freezing. Here is my scenario for memorizing two or three words:
There is a guy sleeping in my bed named Corey. I don't know, he's some random guy I met somewhere. However, when he got home, he ended up freezing on my bed. He is encased in ice. Poor Corey. Now when I see Corey, upon traversing my memory palace, I think Kori as in ice in Japanese. To the right of the bed, under the table, a girl is trying to eat away at the table because she is so damn hungry. lol There is the verb to eat in Japanese. the hungry girl reminds me of eating and table reminds me of the similar word structure. The word is taberu in Japanese. Finally, I see a toy car in my trash can that seems to be dancing to some kind of rumba music. I just conjure the image of the dancing car in my mind when I approach my trash can, and car and rumba is a weird combination of letters that do well in reminding me that the word for car in Japanese is curuma.
You could say that some of these scenarios stretch reality, but that's the point. All of us seem to do better when we have some mental picture associated to an abstract concept of sorts.

I haven't used this specific technique, but I've been using associative memory techniques for a long time. I find that if I need to memorize a number I can, but if I dont' need it for say six months, it becomes vague because it's just an abstract set of digits. So I'll be thinking, it was something like 359 or 395, cant' quite recall. But if you associate it with something solid, it seems to be easier to retrieve after a long period of non-use. For instance, the last six digits of my phone number are 357303. So, for that I'd think 357 magnum and 303 bullet. It's not always as neat as this, but you can usually find something if you think for a while. I'm 45 now, and my short term memory has started to deteriorate over the past year or so. Like I'm playing eurofly at the moment, and they'll announce the runway, and after I've pissed around setting the transponder code and checking my take off speed, I'm thinking what the hell was the runway again. That wasn't happening last time I played it 18 months ago or whatever. So now I'm having to think things like number 1 piss, 2, shit, 3  magic, B2 bomber, A4 paper, etc. It sounds weird as fuck, but it helps. But this memory palace system seems very interesting, and I'm going to try it.

Personally, spacial visualisation has never been my strong suit, indeed I sort of do the reverse of memory palace in that I memorise sets of spacial directions or landmarks via a system of key words or associated concepts, EG go out the door turn left, look for the blue gate and cross the road, go through the archway and turn right etc.

For me, its all about rhythm, colour and language, so if I have to memorise a long number I tend to clump it together into three or four digit rhythmical groups, where as learning music I do  with synaesthesic colour associations, forming specific sets of colours or the like to associate different aspects of the melody.

similarly, when I was learning vocabulary, or when I'm learning  for a peace of music in a language other than English, I have to break it down into some sort of syntactic structure so that I can learn it in smaller patternns, and of course repeat it myself vocally until I can get it right, indeed usually if I can learn to say it, I can learn to recall it (one reason why Simon games are far easier on the Alexa for me than on the computer or mobile devices).

Again though, it depends upon how your memory works. I suspect I have miner issues myself in spacial comprehension so I have used basic memory to compensate, similarly not having access to a notepad or easy way of taking braille notes much of the time my own memory gets the work out instead, indeed one odd thing is I could probably real off the part for every production I've ever played in, but the one time I was in a choral concert with brailled words, I couldn't tell you more than a third of them .
Either way whatever works, ironically, for me the main problem with memorisation is simply that unless I fix memorise something by repeating it vocally or finding a rhythmic exercise, memories tend to get overwhelmed by  whatever is going on in my brain, and in trying to remember something, I'll end up analysing something else in depth, which is probably why people tend to describe me as something like the stereotypical absent minded professor .

I don't see that there is a conflict here, Just as I say, I don't have trouble committing things to memory, I just don't have a short term memory.