few reasons:

• chromes bookmark bar is better. it lets you create icon-only bookmarks and folders.
• the chrome dev tools are much better (i am a web developer)
• chrome lets you install PWA's as apps on your macbook, for example youtube. this is actually huge.
• randomly getting "this page is using too much memory" is annoying, i have an m1 pro with high RAM, memory is not an issue
• chrome uses chromium, an engine that is worlds better than safari's. safari still has random glitches in some websites, and hasn't adopted a lot of javascript standards (like the fetch api)

the only thing i found safari better for was the reading list. chrome has one now, but theres no way to assign a keyboard shortcut to it. hoping this comes in the near future.

also, the new version of safari coming out looks like a step backwards. i don't need a bunch of extra steps to do basic stuff. i actually kind of wish apple would let browsers on iphone implement their own engine instead of just being safari skins.