Web browsers are the most resource intensive apps these days. Dedicated app doesn’t have to run JavaScript or ask for UI elements over network so it’s better for both battery and bandwidth.

It’s quite likely that Switch 2 have been in production for a couple of years already given massive stockpiles they had for release. There’s plenty of circumstantial evidence that they delayed Switch 2 because Switch 1 was selling like hotcakes and there was no good launch lineup.