These are really just really low budget titles being put on 3DS so it doesn't look like it's been abandoned straight away. Of course they'd do better on Switch, but that isn't really their purpose.
Ninty is just trying to mask the fact that they've moved on long enough to sell a few million more 3DSs this year and next. As these games fail, and systems sold starts to drop into Wii U territory, Nintendo will officially kill it.
Retro Tech Select - My Youtube channel. Covers throwback consumer electronics with a focus on "vid'ya games."