Depends how far you are going to wire and what equipment you are going to operate. If your going to operate small 4 wheel switchers, streetcars (IE Bachmanns Birney) non-insulated is a must to keep power contact to the most wheels possible. Old Tyco bobber streetcar had only 2 wheel pickup. But run overhead yo'd rewire the wheels common so you get 2 wheel pickup and the wire. (poles) Non-insulated is always better but expect to do wiring (which aint that tough really)
Newer Atlas Customline switches are coming with a metal frog but insulated, so if you desired you can power the frog up. (smart) The Snap switches still have the insulated frog.
Most newer equipment today has far better wheel pickups than the older equipment like older brass steam using engine right wheel pickup and tender left wheel pickup, often they have enough pickup not needing modding.
So most newer locos will go right thru the insulated frog fine because of plenty of wheel pickup.