>>51445530There's a difference, they permanently change to a gen 7 format, (hell, their entire stat spread changes because gens 1 and 2 calculated IVs and EVs completely different than gens 3 and above,) and all of the things like Pokemon species and moves that existed in gens 1 and 2 still existed in the games after that so they were able to just leave it the same.
If they made Home connect to Stadium, they would have to recode the entire game to recognize something besides the different games that were in the first two gens, implement a system like the Time Capsule in gen 2 where it blocks any Pokemon or moves that were created afterwards, and have to do a reverse of the kinda math that Poke Transporter does to convert the stats of each Pokemon to a valid gen 1 and 2 spread.
It's different cuz Poke Transporter is taking something out from something old and putting it in something new. In this case you'd have to recode the entirety of something old to take something new. Why the hell would they do that?