As a Roblox developer, it is currently too hard to test your game in Play Solo mode in the mobile emulator provided in Studio, because you cannot move your character with WASD or jump with spacebar. Oddly enough, however, you can equip/unequip tools in your backpack with the top row number keys.
Since you only have your mouse cursor to use, you can only do one thing at a time. This means that you cannot move your character and pan the camera, jump, or interact with UI in conjunction. This ultimately makes it harder to test certain game features and even gets your character stuck in certain parts of the map as shown below.
I think we can count on the thumbstick and jump button to be working with no problem every time, so requiring them to be used in the emulator for character movement seems quite unnecessary and problematic at times. Simply allowing WASD and spacebar for character movement would improve this greatly and make the mobile development experience much more intuitive.