As pointed out below, quite a lot of that isn't in RAM - see "working set".

There's a common noob complaint about "Linux using all my RAM!" where people are confused about the headline free/buffers numbers. If there's a reasonable chance data could be used again soon it's better to leave it in RAM; if the RAM is needed for something else, the current contents will get paged out. Having a chunk of RAM be genuinely unallocated to anything is doing nothing for you.

Nitpick: What you're describing is the disk cache. If a process requests more memory than is free, the OS will not page out pages used for the cache, it will simply either release them (if they're on the read cache) or flush them (if they're on the write cache).

Of course it's doing something for you. Room to defrag other areas of RAM, room to load something new without moving something else out of the way first.

Your perspective sounds like the concept that space in a room does nothing for you until/unless you cram it full of hoarded items.

If we're talking about a storage locker that's instantly reconfigurable then it is probably better to be approximately filling it.

Why would anyone buy a locker 5x the size of their needs ?

If you didn't have the "random" buffers, you'd complain how slow it is. Syntax highlighting? Needs a boatload of caching to be efficient. Code search? Hey, you want a cached code index. Plugins? Gotta run your python code somewhere.

Run vi/nano/micro/joe - they're optimizing for memory to some extent. vi clocks in at under 8 MB. You're giving up a lot of "nice" things to get there.