Why upgrade from Home XP pro

I’m reading the threads about people upgrading from the pre-loaded Home Edition XP Pro 2002 SP3 (after updates) which is what came on my PC as well.
Everything works great so why are people trying to change it?
I also read that XP can emulate DOS.
Does that mean I can salvage my old DOS programs like AutoCad? My old computer works and has Windows 98 which allowed you to switch to DOS for all the old DOS games etc. I’m quite sure all the money spent on Legal Law partner and 3D Designer etc is lost money unless I keep the old computer for occassional use.