Like I've said in these comments, I'm constantly surprised by which settings people change and which ones they don't, so differing opinions on exa's defaults is nothing new. exa shares my opinion of wanting to see thousand separators and byte suffixes by default; ls, on the other hand, has no opinion because with file sizes that small, it didn't really have to choose what the output should be like.

People have said that in scripts you'd want to just output the file size in bytes, and they're right, otherwise the numbers won't sort correctly. If you're writing a script, though, you're going to be taking more care than if you were just wanted to list some files. I've lost count of the number of times I've listed a directory, given up trying to count the digits of the file sizes, then re-ran the command with `ls -h`, but I've never written a script without thinking about what the output should be like.

I think your perception of filesizes is slightly skewed; "nine or more digits" means roughly >=100MB. Disk images, software, and videos would be in that range, but probably not the average MP3 (100MB of 320k MP3 is over 40 minutes), and I don't think I've ever handled a "word processing document" more than a few dozen MB --- and even that would already be many hundreds of pages.

Of the files sitting on my desktop at the moment, which is not necessarily representative nor typical but covers a wide range of types (pdf, mp3, zip, exe, jpg, mp4, ...), slightly more than 10% are 10MB or more (8 digits), ~15% have 7 digits (1-9MB), and the rest are below 1MB (<= 6 digits).

Even then, most of my documents are quite a bit smaller, as I have a tendency to write my documents in wordpad instead of office, and then save as rtf or txt.

How does 524404648 vs 5.24404648e8 look?