Removing a Background

Can anyone tell my why I can remove a background in Adobe Express with one click of a button, but can't do that in Photoshop, which is much more powerful. In Photoshop, I usually use the polygon lasso to create a smmoth, clean outline of the subject... which can be very time consuming. But in in Adobe Express, I just click one button and it's done... why can't Photoshop have that same feature?? Thank you!