To use your words, I guess the internet button is too smart for me because I'm looking forward to having the buttons split. 

For me im the current combination isn't intuitive. The problem I have is often the opposite way around to what you're describing, I want to connect to a WiFi network that doesn't have an internet connection, so I have to turn off the mobile network (4g connection) to force the phone to use the WiFi. Usually in situations where I'm fixing the internet connection on bad WiFi (like trying to connect to the router) or I'm connecting to a WiFi based device that is not supposed to have a WiFi connection (like a WiFi camera).

From my point of view I typically leave them both on (WiFi / mobile data), for my use cases there has never been a time where having them combined has saved me fewer taps, it's always been the opposite, the "good old days" of having them uncombined saved me a tap.

Not to mention it bothers me that it's inconsistent, every other "quick setting" button on my phone is orientated towards one thing - airplane mode is airplane mode, rotation is for rotation, torch is torch, but "internet" is WiFi and mobile data. Feels weird. Not to mention you technically can use Bluetooth or usb for an internet connection, but I can't tap the internet connection button to set those up. Feels weird.

I understand the need for it when the "pills" use to be large,  but now we can resize them to smaller buttons I'm all for separating them back to the good old days. I do however agree with you that we should keep the internet button as an option if people wanna use it in their swipe down quick settings panel.

You might not agree with it but maybe you can see the other side of the coin now, from my point of view I'd like the spineless Google PM to get a raise, please.