I use Alfred for launching apps, emailing contacts, searching websites on my company's intranet, searching external websites, controlling Apple Music, maintaining a clipboard history and pasting from it, jumping to communications articles behind my company's firewall, quickly opening up requests/bugs in internal apps, and a lot more.
You can't use it on Windows. I don't use Windows at work, but sometimes I do need to use it at home, such as when I'm mining cryptocurrency or playing games. I understand why the author doesn't make a Windows version though.
There is no other launcher that I've tried that compares to Alfred. It does everything you'll need and then some. If you ever have any issues, just send an email over to email@example.com. They are very quick to reply and resolve any issues.
It just speeds up my productivity more than anything else. It's an essential tool. The only other app that I use that comes close to increasing my productivity is Keyboard Maestro. That one also increases my productivity quite a bit.