Keeping your rig covered will surely keep it from weathering which will make the outside easier to take care of & will make a big difference when it comes time to trade it in.
While, we don't have the cover you are talking about, but we did cover ours for the first time this year (previously we stored at a facility inside, but didn't get reservation in on time this year) with an ADCO AquaShed rv cover. For us, the cover was more bother than worth. As much as we tried to forsee edges that would poke through it & pad them, we've got at least four 3" holes in ours where the awning toppers are. The winds were really bad this year & there was just no way to keep all the edges, even the blunt ones, from working through the cover in several areas. I've also heard others say that the winds can cause the covers to rub paint & roof areas (no matter how well tied down) & can promote mold even with the "breatheable" covers. Our rig is stored over an hour away from us, so we won't know the status of our paint/roof until we uncover it in about a month.
Ours does have several zippered access points & when placed in the right areas of the coach, provided easy access to the entry door & bay doors.
We are currently pricing motorhome ports. Indoor rented storage in our area is quite expensive & many places contract for no less than 6 months whether you store for that long or not. Running the numbers, for the price of a few seasons of rented storage we can get a built port that'll last.
I suppose any cover is better than none. Hopefully, other members will chime in on their experiences with rv covers.