PuTTY is (or was, in the years before WSL) the go-to SSH client for Windows. If you're a Windows user getting onboarded at a job / uni class which uses Linux machines, installing it is the first thing you'd be told. The laptop in question would obviously have a terminal emulator and SSH client pre-installed, but a Windows user wouldn't think to look for them, and they might not even know that SSH exists outside of PuTTY or that it's a separate concept to the terminal.