depends on what you want to do with ur bitcoin. If you want to spend it regularly from your mobile wallet, then watch-only is probably not for you. If you want more of a cold storage setup and use it mostly to receive only / stack sats (to generate receive addresses and check your balance), then watch-only is a great option. Better security for sure. I use watch-only mobile using Blue Wallet for a small amount of btc. Hope that helps.