The problem is no gameplay has been shown at all. Until I've seen gameplay I'm not convinced. We have no idea how long they've been working on Bayonetta 3 because they haven't announced a release date and had just shown a really short cinematic trailer and nothing else.
important to keep in mind that lately Nintendo has not been showing gameplay of upcoming games until prettyyyy close to their release. Almost all of their big 2017 games we saw less than a year before they launched. Odyssey at the Switch announcement video, Arms / Splatoon 2 at the January big Switch Event, etc.
It would be very in line with Nintendo's recent trends to show footage of a number of games at the start of the year that will be out in 2018 and haven't been talked about yet. I mean OBVIOUSLY it's going to happen with some big titles we've yet to see as Nintendo currently has very very little announced officially (Bayonetta bundle, Bayonetta 3, Yoshi, Fire Emblem, Kirby being basically it)