> Who is still using these machines? Genuine question, not trolling.

Either legacy systems (which are most certainly not running the current bleeding-edge Debian) or retro computing enthusiast.

These platforms are long obsolete and there are no practical reasons to run them besides "I have a box in the corner that's running untouched for the last 20 years" and "for fun". I can get a more powerful and power efficient computer (than any of these systems) from my local e-waste recycling facility for free.