Imagine getting on plane with that. Looks like a bomb.
Make a case for it out of an old cereal box, should be fine.
Put it inside one of those bulky toys that look like phones. Might work.
With these mobile raspberry pi projects, for me, the problem has always be how to pack the battery along with a screen and the board in a case.
There are cases with a screen slot, but rather pointless as the device is not portable as long as it does not have a battery.
Often it is “for the battery, use a microusb power bank” (and DO NOT touch to the cable or there will be a reset if you move it too much).
You need a 3d printer for a specific battery product for that.
Still very nice to see how inexpensive and straightforward a phone project can be.
A bigger screen and a port of Sailfish OS would make this even more interesting, as SFOS is already established. Though I don’t know what the problems might be in porting, as afaiu they all have an android base, but that’s probably easy to make pure Linux.
And a better screen might blow the lid off the price.