Outside storage..a quality cover is a must!
But One of The advantage of a smallish Rig is the ease of launching and recovery...
A lot will depend on location ...
But Sky is not the place for LONG periods mooring of a small craft if you can possibly avoid it. (with or without a cover)IMO.
I've seen biggish un-covered RIBs soon fill with water when Bilges have failed in Highland storms which can lead to all sorts of problems ...including capsize!
ESPECIALLY if the wind gets up too!
As with so much in the Highlands ...so much depends on the weather forecast
If you're talking about holiday periods of a week or two ...and the forecast is good day to day ..AND you're confident you're Auto Bilge is good (I have two).
And provideing you can inspect the Boat every day then there is no need to cover. ...It's what we do.
In other circumstances personally I'd recover the RIB each time.