Cat space is very different than monohull space. Berths on monohulls are sometimes more comfortable and sometimes not. It depends on the particular boat. The same length cat, though, has much more usable "living" space but IME smaller cats are cramped in the amas for berths and heads. Costs of cats rise very quickly with length.
I have a monohull right now and one of the big reasons is the cost of moorage in
marinas (for now while not offshore). Cat moorage is double for the same length. That's not a problem in
anchorages. I can't speak to Med-tie style moorage cost. But moorage cost is usually not as big a factor
offshore cruising.
Getting hauled can be a challenge for bigger cats from what I have heard. Big countries with lots of
marinas it should be no problem. But smaller countries it might be if they don't have suitable lifts.
The reason cats seem so attractive to me, other than their seakindlyness, is the "public" space in the
salon and the aft
deck. Even a small cat has better socializing space than the same size mono.
One big factor on cats is two engines versus one. Cost and labor (yours or mechanics) is double.
Wiring is a bit more complicated and controls are duplicated, thruhulls, etc.
As noted, the same length cat is way more expensive to buy than a mono other things being equal such as quality, age, condition.
I like cats and I like monohulls. They are just different in some ways, pro and con, depending on what is important to you.