Nmts are only used for nmt islands, which people need a lot of because RNGsus is finding their dreamies. Even though amiibo cards can get any villager, the amiibo market before re-release was (actually, still is) expensive, so other than using the camping trick, people take their chances with the random nook mile islands. Nmts became the most valuable currency to players, more than bells, and it got so bad that people were and still are willing to pay real money for them. Obviously, Nintendo doesn't like the idea of people paying others real money for their IPs. But going after the illegal salespeople would be a fools errand, because taking one down will have them replaced by another, and they'd be hydra fighting for years if they tried this. Now here comes 2.0 and especially HHP. If HHP works the same way as HHD did, then you may eventually see every villager at random wandering in front of the main building in order to talk to them and build their vacation home(outside of those already living on your island). You could use amiibo to get them right away, but amiibos are hard to find, so most people will probably wait till whoever they're looking for shows up at random. Once you build their home, you can visit them whenever you want. Even if that villager never moves to your island, you can still see, visit, and interact and talk with that villager just by visiting them in their vacation home. For a lot of people(but not everyone obviously), this may make them feel less pressured to random search to bring their favorite dreamie into their island. They'll probably not look as much to find their dreamie if they can still talk or interact with them everyday in the vacation house.
Also, Nintendo made it so that everything new in 2.0 needs nook mile points instead of nook mile tickets. Kap'n? points. New Nook mile furniture? points. With HHP you'll be building vacation homes, and will be earning points. Unlike the tickets, points can't be transferred to another player. I think with the pressure off for finding dreamies with HHP, and (so far) very little being seen in 2.0 needing nmts instead of points, a lot of people may not want nmts as much as they do now.
Also, Nintendo made it so that everything new in 2.0 needs nook mile points instead of nook mile tickets. Kap'n? points. New Nook mile furniture? points. With HHP you'll be building vacation homes, and will be earning points. Unlike the tickets, points can't be transferred to another player. I think with the pressure off for finding dreamies with HHP, and (so far) very little being seen in 2.0 needing nmts instead of points, a lot of people may not want nmts as much as they do now.