No.
I have never used a spray cover on my SRT and, with one early exception, on any of my 13 open canoes—even my specialized whitewater canoes with which I used to run class 3 and 4 whitewater regularly for 18 years. In fact, I never saw a spray cover on any whitewater canoe in any whitewater club I ever paddled with. People used big float bags, carried bailers, and dumped water out of canoes periodically on the shore. Not a big deal.
The one exception was in my pink elephant, buy-every-gadget, whitewater novice period with my first canoe, a Mad River Explorer back in 1980. I had a three-cockpit, custom spray cover made for it with zipper-off cockpit covers, spray skirts, and paddle pockets. Snaps under the gunwales. I used this monstrosity a few times on northern California whitewater river trips, including one three-nighter. It was a hassle to put on and remove. After dumping a couple of times in big rapids with the cover on, I decided the whole magilla was actually dangerous and a potential body enwrapment and entrapment contraption in whitewater. I never used it again.
To keep water out of my open canoe in whitewater and waves, I learned over a period of years how to paddle a lot better—including how to avoid water intake with body weight shifting, J-cocking at the hips, and leaning away from waves (especially upstream leaning on a paddle plant)—plus how to scoop-flip water out of a canoe really fast with a Clorox bailer or paddle. Easy-peasy.
Like skid plates and double bladed paddles, canoe covers on open canoes can be a subject with completely differing opinions and experiences.