I do and I dont.
I record the workout using the watch so it appears on my activity, but I use a HRM (or not if I forget) for HR display on the rower.
This is all because my Model D can neither send activity to apple nor connect to the watch for HR.
Even my far more modern wattbike won’t use Apple Watch HR.
I do have a chest HR belt for the rower and somehow ended up with an optical arm HR for the wattbike.
A modern chest strap would do both I’d imagine.