I don't think it's that silly. BusyBox packages a bunch of utilities in a single binary. It amortizes fixed costs: a single binary takes less space than 30 binaries that each do one tiny thing.

These are small bits of code, and the functionality is interrelated. The entire thing feels like a calculator, or awk, and seems reasonable to put in one binary.

The Unix philosophy doesn't actually say anything about whether different tools should live in the same binary. It's about having orthogonal bits of functionality and using text as the universal interface. BusyBox is just as Unix as having all the tools be different binaries.