I personally don’t like a water rower as much .
A traditional rower allows you to set resistance Between 1 and 10 . I train a group of ladies mostly 40-75 years old and I pin the resistance on 10 and leave it there . That may seem odd but The 10 resistance is not that hard and they really enjoy it , the added resistance is also a bit better for bone density thou so that’s part of my bias with their use .
Also , Rowing on a water rower doesn’t seem to have any resistance setting and it feels to me like the resistance is set so low and you just have to increase the speed of your actual rowing to make up the difference. I don’t like that trade off (needing more speed) , unless someone has perfect form and less physical complications.
I am no expert on rowing those are just my experiences and I would say it’s definitely better to use either of them than sit on the couch