Regarding two gear internal hubs: these are amazing! I don’t know this specific hub from SRAM but Sturmey-Archer offers similar flip flop hubs as well that toggle gears by slightly pedaling backwards (S2 iirc). I've built three custom bikes so far with those and since you need no cables for them on your frame you can build very 'clean' looking and mechanically robust bikes. I think Fichtel & Sachs first came up with this idea in the 1970s - nice to see that SRAM is picking it up again.

Edit for clarification: the Sturmey-Archer hubs are built to be used with only one chain of course.