"Your" experience is only applicable to you, unless you know for certain that you are running the same OS, same applications, same games with the same settings and everything else is the same as well. If not, then you have no idea what is "needed" by the OP's system.
I'm not even marginally one of those people who runs extremely demanding professional applications or giant VM's and I easily exceed 16GB on a regular basis, especially if I'm running Virtual Box or any other VM application. But there are plenty of folks who exceed 16GB running ONLY games and multitasking with other software simultaneously OR any of a cart full of professional applications out there that, when used by a professional to perform professional tasks. A single high resolution image with a few layers can practically zero out that 16GB in a lot of graphics applications.
So unless you know they are not doing ANY of that, you really have no idea how much memory anybody needs and since you didn't bother to ASK that question, it seems rather premature to make statements like "it is probably a waste". The bottom line is, you have no idea what is or is not a waste to this or any other users system if you don't know specifically what they are planning to run and at what level of expertise.
Now, if ALL they are doing is running COD: Warzone, then yes, they are never going to come near 16GB usage from game play alone. But if they are running Chrome with ten or more tabs open, overlays, monitoring software, a test VM, photoshop AND Call of duty, then they are probably going to stand a good chance that 16GB won't even remotely be enough to handle the requirements of the software unless they are not using any of it beyond very light, casual use.
However, there are RIGHT NOW, a handful of games that by themselves, along with Windows and whatever background processes are running, can use 16GB. Adding mods, to any game, might greatly increase that need as well, even for games that normally use an average amount of RAM.
Keep in mind that the fact that YOUR system, or ANY system for that matter, isn't using more than 16GB is VERY OFTEN due to the fact that more than 16GB isn't installed. I've seen plenty of configurations with only X amount of RAM that only used Y % of it, but once additional memory was added that figure increased well beyond what was allocated when a lesser capacity was installed. In other words, if you are running a given set of programs and using only 14.8GB total, and then install an additional 16GB, you should not be at ALL surprised to see that afterwards when running the same software you find that the allocation is now beyond 16GB simply because it was not there to be allocated in the beginning but was there and available afterwards. Your system won't try to use what you don't have so the fact that you don't FULLY run out of memory in a configuration does not mean that, if it were there, it wouldn't get used.
There are simply too many variables to say that what IS on one system, IS on another. My recommendation is never to upgrade to 32GB just because I like that number. But I highly recommend that users don't make assumptions either. Whether or not a given amount of memory is wise depends entirely on the specifics of what they are doing, not what you did.