I don't think that question makes much sense.
Obviously on a monohull everybody will be much more concerned about sinking than capsizing. Most capsizes till over 90º (to the AVS) normally don't have serious consequences (and they are by far the more frequent) and even if the boat is inverted in almost all cases a modern cruising monohull will re- right itself, sometimes with serious problems, losing the
mast, losing the
engine, or sometimes with few problems. In very rare cases the boat sinks after re righting itself due to damage that resulted from the capsize.
On some cases the monohull is able to continue sailing normally, on other cases it has to resource to an improvised rig but on the huge majority of cases where the boat is not able to continue sailing if offers a safe shelter till a
rescue takes place.
Anyway note that the vast majority of rescues to monohulls happened after the boat having capsized (not rolled) several times or because a risk of capsize is feared .Most boats where a crew
rescue takes place are in sailing condition or with shredded sails, but not risking imminent sinking. One has only to look at the movies taken by the rescuers, they are many on the net.
Normally the
skipper says that the boat is making
water, even if we can see on many movies that the boats sits normally on their waterline. I believe they say that for
insurance coverage and they are abandoning the boat not because they are in
danger but because they are afraid they may be, if they continue sailing.
Even if some monohulls are unsinkable due to waterproof compartments, unsinkability is much more common on cats even if some have sunk after capsizing.
When a cat capsizes in good weather conditions and does not sink, it can offer a survival platform, a wet one and probably offering worst survival conditions than a good
offshore life raft, where one is protected from the cold.
But if the capsize happens in strong weather then staying attached to a platform with breakers going over it is very difficult or impossible and many have died after a cat capsize due to not being able to remain over the capsized cat or for exposition to the cold water.
Even on a cat, an
offshore liferaft, that can be released with the cat capsized, is fundamental for the
safety of the crew.
Answering directly to your question, if for a monohull sailor a capsize is not normally the end of the line and therefore they are much more afraid of sinking (even if they can resource to the liferaft) for a cat sailor a capsize can be the end of the line, the boat is not going re right itself, no possibility of continuing sailing after that and the ability to stay over the cat waiting for help with bad sea conditions is certainly no bigger, in what regards survival conditions, than staying on an offhore
liferaft ....and many cats don't carry a liferaft or carry one that cannot be deployed with the boat inverted.
So, it is normal to have different fears, I mean on the rare occasions where there is something to fear. Many or most will never pass by a situation where fear may be justifiable.