It's not installing PuTTY, it's using it. Normally you have a fully-fledged programming language that sometimes runs a command being SSH client, and universal

It's not installing PuTTY, it's using it. Normally you have a fully-fledged programming language that sometimes runs a command being SSH client, and universal one at that (you can pipe data through it, you can pipe data out of it, you can run remote commands non-interactively with it, you can jump through SSH on other hosts with it, you can set up TCP tunnels in ad-hoc manner without going through the configuration, and obviously you can run an interactive shell). Plus you get scp for file transfer out of the box, and lftp (which understands sftp protocol) and rsync after installing some barely related software, all of them still able to jump through other hosts. Now compare it to the glorious ability to open a window with remote shell (and only direct one, no jumping through a bastion host), and maybe a TCP tunnel with some clicking through every single time (you can't recall the history of commands, because there was no command in the first place; the best you can do is to save the tunnel configuration permanently). And maybe file transfer if you remembered to download PuTTY's scp client.