Differences between pokemon NDS ROM & Original Copy now that nds is discontinued?

I'd like to know the differences between the pokemon (any generation, idk, pokemon white 2 for example) roms and original games now that nintendo no more support some of its features! thank you :))

a rom is a perfect copy of the game cartridge, there's no difference and never was.

Replying to #2

i mean, differences in use of features, like wireless/online trading and stuff. For example, i use flashcards. What are the things i can do in a pokemon game, and what i cant because it isnt a legit copy?

None of the online features are available on either rom or legit to my knowledge, but other than that everything should work regardless of whether its a rom or a genuine cartridge