To add to what @Satinel alluded to with getting people to play your game, if your game works as a WebGL build, allowing people to play in their browser will generally result in more people trying it out since it makes that process simpler. Having a smaller download size is the next best thing. Of course, if you have a 750MB download and the game is exceptional and generates glowing comments and word of mouth, it'll get good attention anyway.
As a nerd, I have to point out how good an exercise it is to learn to optimize the assets used and the size of the build, so good for you for delving into that ahead of time. Especially if you ever intend to develop for mobile, build size can be a really big deal.