I sailed an 18' catboat for 15 years and remain impressed with their ability to deal with adverse conditions. I was also familiar with a fellow who owned an AC 24 who sailed and raced it in our area (coastal SE New England) and he absolutely loved it. He even took it to the Chesapeake shortly before he passed away. I was even considering an AC 24 before I found my swing keel 35 ft sloop 17 years ago.
You are correct that you don't want to gybe a catboat in higher winds, but, that said, I have watched catboats gybe in one race where the winds hit 30 knots. Several of the catboats deliberately gybed coming around the mark to the downwind leg. Two of them ended up with what we called a "gooseneck gybe", wherein the boom lifts high as it comes around and--this case--ripped the sail. A third (single-handed by a 75 yr.old woman) actually broke the gooseneck fitting. These 3 boats withdrew from the race at that point.
These were not accidental gybes, but what I would call "hotdogging" in race mode. Usually you have plenty of warning of an impending gybe and can react in time. I find my sloop is quicker to gybe than my old catboat. When you gybe in higher winds in a catboat, what can happen is that the momentum of the boom, along with the tendency of a catboat to head up when overpowered, is that the catboat will do just that and you will keep turning and head up. It actually is quite funny to watch when a catboat sailor does this in the heat of a race!
During that same race, I shook out a reef at 20 kts, just before the winds picked up to 30 kts. Big mistake! Not willing to go forward to reef at that point, I continued with full sail, using a fisherman's reef (ease the mainsheet and let the sail flog a bit) which is not good for the sail. Being in last place, I went through the wind at that downwind mark and --being overpowered--used a standard catboat trick when caught in this situation, which is to "scandalize". That is, to drop the gaff. You immediately dump the wind from about 2/3 of the sail and move the center of effort lower and closer to the centerline.
When you inevitably get caught in conditions you'd rather not be in, you learn a lot about your boat. What I've learned about catboats is that they are extremely stable and safe. You typically cannot get the rail down. As the catboat becomes overpowered it heads up with a weather helm that takes over. The wide beam also provides the form stability to keep you on your feet, which makes it harder to get your boom in the water. Besides, catboats don't have vangs and the boom tends to be raised when you are running in a breeze. The picture below shows an 80 yr. old, double-reefed 22ft Crosby cat running downwind in what looks like about a 20 kt+ breeze. I have never had a problem with the boom snagging the water when running and I've sailed the 18 footer in an area bounded by Wickford, RI, to Block Island to Shelter Island.
The catboat design was a day in , day out work boat that had to be reasonably well-behaved and easily managed over a variety of conditions. Those mannerisms are maintained in the fiberglass replicas you see today. They are not blue water boats, primarily due to the large cockpits (you don't want to get pooped in a catboat).
I'll be downsizing one of these days and would consider going back to an 18-22 ft catboat. That 75 yr.old lady who sailed her 18 ft catboat in 30 kts is my role model--not that I would deliberately go out in 30 kts!