While I rarely carry a net (because I don't take pictures of fish any more and I really don't care if I lose a fish I'm going to release), one situation where I always carry a net (so I don't hurt the fish) is when fishing from the bank.
Often times the stream bank is considerably higher than the water's surface or I am at other places like the wall at the Run. In those situations a long handled net is the ticket.
The kind I use are aluminum, telescoping & collapsible and they fold up small enough to fit in a scabbard on my belt.