Shadow kitchens that make recipes for multiple different restaurants could have measurements in both.
To not have the button at all would make sense(compile time config), but if there are situations where you need to change it, those can come up as frequently as every time you use it
Every commercial kitchen complies with and is inspected for compliance with food handling regulations.
Any recipe in commercial use is written specifically for the kitchen in which it is made. One might even consider them a complete vertical unit: if the recipe is designed as a chain or franchise standard, the kitchen standard is designed in tandem to match.
You will not find a commercial kitchen in America using Celsius for anything.
If you don't want professional tools don't buy them.
Having a button that changes it with a single press is actually an impediment to working quickly, and only introduces uncertainty and anxiety about the tool. Measuring temperature isn't like measuring weight - seconds matter. A moment of confusion could be enough to ruin a process, and a failure to notice the change in settings could create a dangerous situation. Nobody wants a button to see the wrong number.
Think of it like compile-time config. It's there, you can change it if you want, and everyone will have a preference, but if you need to change it often, you're not the target market.
In the rare consumer case in which you may be using foreign measurements you can change it once at the beginning of the recipe.