Main reason to sanitize or QT plants is to prevent hitchhikers like snails, scuds, etc., from getting into the main tank, or to clean them up if they have algae. If you buy good plants, shouldn't be any algae, and hopefully, few hitchhikers.
But I like to keep them in a bucket for a day or two. They have a light, an air stone for circulation and if there are any hitchhikers, they usually show up on the bucket bottom or walls. Not 100% effective, by any means, but gives me an idea if something I got has anything on it. If it has pest snails, I could then dip them if I wanted to, to kill the snails, before I plant them.
If I get scuds, I put them in a tank with all the others I've come across. Loaches like to eat them and they actually do an amazing job of eating algae off plant leaves. If I get an infested plant, I drop it into the scud tank for them to clean. They do it way better than I can, and no chemicals required. But of course, one must have a tank to keep them in if you don't want them in a main tank. They're pretty harmless unless they are starving, in which case live plants become lunch too. I give them pellets to prevent that happening.