When ram is less than 4gb, i use i686. Of course you could also ask: Is there anyone with less than 4gb of ram? And the answer is: yes, and they should stick to i686 simply because 32bit apps consume less ram.
To avoid throwing away old gear, even if linux drops support for the older 32bit cpus, you could always use something like Netbsd, which still officially supports i486. I particularly use OpenBSD with very old machines, simply because you can (net)install it using a single floppy.
A typical Pentium might not have usb, but usually has a floppy drive.
And if you still thinking why?, well there are enthusiasts, and there are people living in poverty or in countries with serious problems.
These computers used to run w9x which has long been abandoned, and yet they can still be useful with a modern *nix like OS. If it works, and getting Raspis is impossible; why not?