OP, I used to use a Covercraft cover on my ride that I had to park outside back in the day... I agree there can be benefits to a cover, but the challenge as some have said is, if your vehicle is dirty at all, as you put the cover on and take it off, you WILL introduce micro scratches onto your finish -- plus the inside of the cover will retain some of that dirt, compounding the problem as time goes on. The covers can be washed a few times, but not a lot before they will be damaged in some way. IMHO, an outside cover only works if you're going to have a clean ride parked for a period of time. I wouldn't use one unless I decided to take the micro scratch problem I described, over say more extensive bird @#$& or sap that may sit on my finish doing even more extensive damage through your protection layer before it hits your clearcoat.
OTOH, for years I have kept my previous 2nd-car "toys" (hardtop convertibles) inside my garages, under their extremely soft (and not weather resistant) dust covers once they are dried from one of my wash & detailing sessions between outings. It keeps them in pristine shape until the next outing, and requires less than 5 mins for me to roll the cover up, put it in it's bag, hop in and go.