Obviously it's not feasible for everyone to make a webGL build of their game, but for me, at least, I am mostly likely to only play games that have a webGL version, and for a few reasons I would personally recommend building your game with the intention and plan to publish to webGL for a few reasons:

First: discoverability. Downloading an executable takes time and effort, and a lot of people, myself included, are going to find it way easier to click a page and get playing rather than downloading, unzipping, and then running an executable. Also...

Second: security. I had a friend who recently got hit with a pretty bad virus when someone spoofed a fellow game developer and sent him a virus disguised as a game they wanted "playtested". This kind of social engineering could happen to anyone.

My personal line in the sand is that, for the most part, I am only going to play and rate games with a WebGL version. My original version of this post was a bit overly snippy, I admit, but hopefully this one better explains.

EDIT: I re-wrote the post because it was more condescending in tone than I intended, also, uh... I have been informed that the meme I used is passive aggressive? I literally thought it was a pleading meme... I swear to god I am never using memes ever again...