I'm not sure we'll start out with sufficient funds to do that for each user.
You don't need to open a channel to every single user. You could open a single large channel to some medium/large sized node which could take care of payment routing for a small fee.
When some node routes a payment, it receives coins in one channel and uses some other channel to send the same amount of coins (minus the fee).
You could even open a direct channel to
BlueWallet node to make sure that there would not be any failed routings. Also, you would not be paying an off-chain transaction fee for every withdrawal made to BlueWallet.