That's an awesome find. The hinged ones Riv sells are "easier" to install for folks who already have their grips installed and can't/don't want to remove them, but for a fresh flat bar build, those Microshifts are awesome.
The other thing about the Riv ones is that they will fit 26.0mm which can be super slick if you want to put it on the tops of your Noodle bars. For those using them as 22.2mm shifters, that may be a downgrade, because you have to use shims, and you'll probably be annoyed if you lose one.
Anyway, a set of each in the shifter box would be a strong nice-to-have.