The addition of the accessibility second controller my day! My partner has a medical issue that caused her to lose a lot of mobility and it causes a great deal of pain to hold a standard controller (and joycons are too small for her to grip comfortably). A while back, we'd tested the ergonomics of this hypothetical setup for her condition and found it would work.
She's been wanting to play games again for a year now and the split controller accessibility option will let her do that.