I agree. I was thinking about this today when using my HTC's The data connection dropped out so the maps and other data took forEVER to load. The GPS signals worked great but without knowing where I was trying to get to, they were useless.
So, smart phones are great for urban caching, satellite maps, posting of logs and pictures on the fly but only as long as a good data connection exists. So I'd say use it till you decide you want to spend the money to buy a GPSr and are really into this hobby.