Yeah and the use case of keeping it on your phone available to you is to generate receive addresses & confirm that you received the Bitcoins you were expecting to.

Remember, if you're accepting payment from someone it's better to use a new receive address generated by your watch only wallet, that way they can't see the address with your main stack in it - yet you can still conveniently accept new Bitcoins into your possession meanwhile your SeedWords & HWW sit in a secure location.