USB modes, for transfering files with AFT Why do I have to go into the phone (Galaxy S7 Edge) everytime I connect it to my Mac and manually switch the USB option from charging to MTP??

This is annoying and a hassle, why can't the phone detect that its plugged in and switch modes itself?

I dont want to have the phone in developer mode all the time, i just disabled it because its not applicable to me but now I have to turn it on every time I want to transfer files onto my phone. 

There has to be a better way to do this.
Any explanations?
You have to change it every time because of security changes in Android, and there is no easy way around it without root on a stock device. 

The reason is so anyone can't just connect to your phone without screen being unlocked, it is purely a security enhancement.