>> I know that this is a silly question, but...
>> what, primarily is the purpose of the car cover?
>> To protect from Snow?  Salt?  UV?  Dents?  All of these?

I cover mine with a tarp and bungee it, but this I do, when  I park the
van for weeks at a time. Too inconvenient for just a few days. My
motive, is to keep the blistering Utah sun off the rubber window seals,
the vinyl seats, dashboard, etc. Plus, the paint is faded bad enough as
it is, so even if its not UV proof, its better than nothing. Its doesn't
rain much, so moisture isn't that big a deal here. The wind blows pretty
good tho, and since the tarp isn't all that taught, it balloons up, and
any moisture will get dried right out. Might be more of a psychological
thing as much as a necessity. The sun will just tear your hide off, so I
try to help my van as best I can.

When I put it to bed for the coldest winter months, I usually don't
cover it, but the sun is so low at those times, that I don't think of it
as being much of a threat.

I would love to buy one of those freestanding "tarp garages" one day.
Seems like that would be the best, but for now, the money goes to
getting it running, and keeping it that way :-)