Anyone wants to try this out, install the Beta version of Signal and send some mobilecoin to me at
iHXtgfsScSiaqKFMev8mC5Yogz8uZhTJSUVBM1vkECKPaVVxp9woYvbZJPso4SNx5oCkiU5XrAGZj6XwZMrYGzQztntDUKRka2RHnc6d9NPYaorT7E21jEWobERA77Uzny4VoeChDA9m2MihDLTB47BoJ3S2Lhuhp8U Kbo6jyRpo2zcr5ZucssuBVENGUS4fTK7qZZY8qMXHd9B1MNbA2MgBBzb5fBjberr6v4NKBVo3oFNCS1J3ryX13ZszByxjEU
The UI seems fairly unobtrusive, but I don't know if that's just because I have no contacts that can receive it so I'm not being shown some of it.
I also have no idea how to actually get Mobilecoin to play with. There's no built in way to buy it. They just give you an address you can send to from an exchange.