Probably a very small amount of people abusing it somehow (How a lot of files can be abused i dont know), like how a small amount of people abused the old gsuite unlimited plan to store petabytes for $12/m
Then why doesn't Google use their standard solution and just ban those vanishingly few users, pointing to an ambiguous "terms of service violation" and then ignoring all their support requests for a lifetime?
How is that better than just limiting their account until they delete the files?
It's not better, but based on past occurrences it seems to be the favorite method applied by Google and <insert any multi-billion IT corporation>.