Earlier quoted context omitted.
For me it's the other way round, i've been trying to use Firefox but the "pinch to zoom" feature in Safari is so smooth, and so crappy in Firefox, that i always keep coming back to Safari... If you read a lot of text on a Macbook, being able to zoom quickly and efficiently becomes a high priority. Things like this are much more important for me than energy-efficiency.
You may want to get a checkup from an optometrist. No joke. I think almost everyone is affected by age-related degeneration of their vision at some point or another.
If i open https://news.ycombinator.com/news on my Macbook pro retina 15" i see news items 1 to 22 in a tiny font.. so i zoom to about 10 items which i find much easier to read (bigger text and less info), and using pinch to zoom you can do it very easily - in Safari.