It's that you're also probably going to get CGNAT - and maybe even a firewall blocking unusual ports.
And you're going to be running the power-hungry data connection at least twice as much, bad for battery life.
And mobile connections are less reliable - transitions between towers, going through tunnels, switching between 4G and WiFi.
And mobile OSes are eager to suspend things - especially things that are using a lot of data and battery.
I'm thinking of the situation where most of the users are using home connections and have power cables always in or in reach.
It's that you're also probably going to get CGNAT - and maybe even a firewall blocking unusual ports.
And you're going to be running the power-hungry data connection at least twice as much, bad for battery life.
And mobile connections are less reliable - transitions between towers, going through tunnels, switching between 4G and WiFi.
And mobile OSes are eager to suspend things - especially things that are using a lot of data and battery.