I see your point, but I think this not made for more comfortably way to validate, instead to have one step further against the bots.
Because it’s not impossible to do this, but is connected with more work to implement to click on a button, and so a bunch of the script-kiddies are defeated already.
Our community ninja @Saoiray may know it even better than me.
Greetings LxWulf 
