This is not about a hype or "looking cool". Mouse and GUIs are faster and more ergonomic for exploratory activities ("how do I do X" for a new task, skimming a document or folder, etc), while keyboard (keyboard shortcuts, command line) is faster for routine, repeatable tasks. Web browsing is full of the latter.
I personally strongly prefer the keyboard and find it exhausting to reach for the mouse all the time, but it's a matter of personal preference. I don't think less of someone when I see they heavily use the mouse when programming, though in my opinion they are missing out.