I can chime in here as someone who works in this domain for over 15 years , there are some drawbacks for more RAM , ill explain a few.It’s possible with low ram, obviously. To say more ram isn’t better is ridiculous. That’s my point. You don’t get that, which is weird.
Just because you can do your stuff with 8gb ram doesn’t mean it doesn’t work better with double the ram.
1) - Timing , the bigger the DRAM the worst its timings can get (CL (read/write latency) for example) , and if you want to keep the better timings you pay more for a faster binned DRAM (doing an activate to a row that is "far" from the sense amplifier is harder to close your timing on , because the data needs to come from further away).
2) BW doesn't change if the DRAM is bigger , so if the SoC can use its OOO in an efficient way it can have all the data it ever needs in the 8GB DRAM (of course some is reserved to the OS and some to other programs) , so here the main benefit of more memory is the fact you can have more programs opened while they sit in the DRAM , but I don't think this is the discussion here , more DRAM =! more BW all the time , it just makes it less likely you will need to fetch something from your SSD , but today systems are not doing a 1 by 1 fetch , i.e if SW needs something from the SSD it doesn't bring 64B of data , and then go again to bring another 64B when the CPU requires it , it brings the data in large chunks and it does it via PRE fetch , i.e it guesses it needs it before the CPU uses it.
3) Power - less DRAM is less power consumed , dynamic and static (so less leakage on Idle) , so for anything battery ran , less DRAM is better for your battery.
There is a big shift of paradigm here , and as we are used to think about RAM == performance , because that's how it USED to be for the majority of users it is hard to come to terms with the fact we can SAVE money and have all the performance we can ever need.
Now , would having more DRAM might help with performance in certain use cases ? of course , no doubt , but those looks to be very non mainstream , to a point where if you do happen to do such a task once every other week , you should still use the 8GB and be OK.
If your day2day work really gets an edge by using more memory , then sure go for it , but I to be honest I didn't see the video/article of a M1 8GB vs M1 16GB in which the 16GB shows its advantage.