What is the difference between remotely installing a game on computer and downloading via Steam?

After purchasing a game via Steam, it gives me two options: Download game remotely to computer; and where it asks "Got Steam?" which on clicking redirects to the Steam Desktop Application and it starts downloading the game. I want to know the difference between the two options.

I assume you're doing this in the browser?

Basically, the "remote install" option will (if you're logged in and Steam is active) give you the ability to install games on a desktop computer that has the Steam client. So if you're on a different computer/mobile device and you want to be able to purchase something and then get Steam to download it to the desktop/laptop you have the Steam Client on, that's the option you'd use. It's useful if you're, say, browsing the Steam sales while on your phone somewhere and want the games to (hopefully) be downloaded and waiting for you when you get back home to your desktop/laptop.

The "Got Steam?" option allows you to download the Steam client to whatever device you're on (laptop/desktop), or if you already have it, will redirect you to it, and then start the download. So it only works if you have the Steam Client already on that device, or plan to download it as part of that process.