Zooming on a Mac with MacOS High Sierra with the pinching motion on a trackpad does zoom the text size but it also changes the layout of dynamic sites. This is very confusing and not a smooth motion.
It also changes the line of text displayed. So when reading a text an zooming, I have to find the right place again.
When zooming in Safari the entire site is just made larger without any layout changes.
This is a very helpful accessibility feature and allows also a closer look at pictures. Please change the zoom style to the one used in Safari.