Makes sense on consoles, not on PC.
Not really - hard drives are about the only part of consoles you can upgrade (because soldering on 256MB of memory makes the product so much better... makes the platform virtually future-proof).
And no, I'm not saying that PCs are superior, just that consoles have singularly dumb features (Would you buy a car if you had to replace the entire car every time you chipped a window? That's just dumb, right? But that's the equivalent of soldered on memory)
What's that good for?
Remember how the game shows you a list of characters? And then a list of saves helpfully presenting you with a screenshot, the in-game location and play time? Where do you think the game gets that information without first reading *all* the save files?
Further, how long would you be prepared to wait for the "load game" menu to come up? I doubt it's longer than 10s, so the maximum number of saves you can have is however many you can read in 10s. If you want to you can modify the game to allow for more saves, and watch it hang for 15min trying to build the character list from 10k save files.
So sorry, unless you are willing to sacrifice all that (e.g. you'd have to remember that save0287 is the elf mage before the final bossfight, save0288 is the new quanari rogue you made, etc) or unless you can come up with a way to read 10k files in less than five seconds, restricting the number of saves is the least bad option.