The distro would have to include FP emulation software for the 486 SX, which is a big chunk of code if a floppy disk is all you have to work with.

Also, some system tools need FP support (like df).

exactly that: too complicated.

also I got 486 DX2/66 as my first PC so I set that as a goal. Then checked how lower can I go. Also I only have 486 DX4 now to test on real hardware.