Do we have confirmation on if Edward, Germain, and other 'manual mode' casters even knew that magic was doing the calculations? I remember it coming across as something Edward hadn't really thought about.

Although considering we already know that the calculations can be offloaded onto tech (the transformation gun, although it seems to use preset values per form), so it's possible that the transformation watches will thematically come back as a more user-friendly but slower wand alternative. Probably as something a bit bigger than a watch though, transformation calculators?

Thankfully spell apps don't seem to be possible, although tools to load spells into a phone might be. I'm guessing that Arthur, Edward, or someone in a similar position is currently making deals as to what kind of spells are legal to sell.