Apple has an app developer story for ipad with swift playgrounds. It would not surprise me that their long term strategy is to grow that into the default app dev experience and have it be on all platforms, including visionOS.
As for developing from day one, web development should be ok, as things like vs code online have really opened ip options.
That said I’ve planned to get one since I heard rumors years ago that this was in the works.
I sort of expected it to be a full replacement for a MacBook though.