In theory I think it could be a good idea, but practically when you want to buy or sell, there also should be the opposite order.
And you forget about one the purposes of cryptocurrency is to burn such shit like centralized money emission.
If you need to sell your btc or alts, you always can use online exchange, local bitcoin, or telegram bots.
The better way for resolving this problem is implementation of crypto in our everyday life,
lightning could be the first step.
P.S. It is extremely unsafe to hold your alts on mobile wallets.