The price difference between 3.5' and 2.5' drives are not that steep. And SSD drives are all 2.5 sized (which the console can use natively).
And does anyone need more than 2TB of console storage? Seriously, delete something.
When some of us were already deleting things less than a year into this consoles life cycle, and games are just going to get bigger, there's a need for more storage.