I’ve been a bit worried about accidentally toggling plugs in the app when my phone is unlocked—like turning off something critical (hello, fridge!). The ability to lock the control button in the app can really save my life.
I don’t know why you’d have a smart plug controlling power to a refrigerator, but that’s your business. 
I’m also not aware of a way to do what you’re suggesting, though I think there’s some value to making control choices for devices more intentional within the app, and I’ve commented elsewhere that I like the way myQ gives users a choice for this within their app’s UI: Users can choose whether a simple single-tap or a press-and-hold is required to open or close a connected garage door. I like how the press-and-hold is a way for the app to be sure that I intend for it to do what I’m indicating and that it’s not merely an accident or errant tap.
To monitor the consumption.
I imagine you mean watts and not calories. 
That makes sense, and I know some smart plugs can do that (the v1 Wyze Plugs I have don’t). Maybe a different tool that doesn’t have a built-in on/off switch would be a better choice for that application?
Regardless, I still agree that it’d be nice for users to at least have the option for the app to require a clearly intentional gesture for powering devices on and off.