Along with Miitomo, a large part of Mario Run's business strategy seems to have been built around getting as many people onto My Nintendo as possible, so I'd actually be more interested in their My Nintendo enrolment rate than their monetisation rate (hopefully we'll get some details at their next quarterly briefing).
How they try to leverage this for Switch's launch will be very interesting. Obviously the mere existence and popularity of Mario Run and the NES Classic is keeping Nintendo in people's minds, but they could also actively push Switch to Mario Run users both directly (advertising it within the game), and indirectly by offering My Nintendo rewards in Mario Run for owning a Switch or vice versa.
I'm most interested in how they use Animal Crossing to try to bring mobile users over to Switch. It's the most mobile-friendly of their large franchises, but it also offers perhaps the most interesting possibilities when it comes to bringing casual gamers on board to their dedicated hardware. It's not something that's coming up a lot in discussions of Switch games this year, but I'd be quite surprised if we don't see an Animal Crossing title early on to tie in with the mobile game. Obviously there would be ample opportunity for typical FTP monetisation in an Animal Crossing mobile game, but with a tie-in Switch game they could use linkage between the two games (e.g. "You've earned this piece of furniture for use in Animal Crossing Switch") to push buying a Switch as their main monetisation strategy. They've already got the My Nintendo-linked cloud save system up and running to handle the interaction between the two games, and they can treat the mobile game as something like the island in existing AC games, sharing the same character across the two, but with new activities and different furniture/clothing/etc. that can be brought back and forth between the two games.