Newer, top-line phones are very water resistant, certainly enough to be fine in a jersey pocket, even in the rain. The iPhone 12 is IP68 rated, for example, so resistant enough to withstand 20ft submerged in water for 30 minutes, pressure far in excess of what it could ever see in the back jersey pocket during a storm.
I’m a dandy, though, and use a
Silca Phone Wallet because it looks good, feels good, and helps me keep organized the little things I carry but which don’t live on the bike, like ID, emergency contact, and credit cards, as well as eyeglass wipes, some cash, a GU pack or two, face mask and a couple alcohol wipes. It’s way nice not having the mask get all damp from a jersey pocket, because that sh*t is gross.
The Silca pouch does have a fixed dry bag, but it’s a *****-and-a-half getting my iP11PM in and out of it. It fits perfectly, and the bag has a clear face through which you can operate the phone, but the way the vinyl films on the phone means you really have to work to wiggle it free, which is too much hassle for unnecessary protection.
The big deal for me is that the wallet neatly collects little stuff I want handy, and saves me from having to remember loose items before each ride, but even out of the drybag and just zipped in the wallet, the wallet offers a nice measure of crash protection to the phone, so I appreciate that, too.