Here are some pros and cons I've been thinking about it but only time will tell if this was the best decision.

Pros: 1) Battle.net launcher is straightforward in terms of getting to the game, updating, and playing. 2)Steam has a little bit of bloat when looking at the store, then selecting your game. You can right click and select the game, but with BNet's launcher, the last game you played will be up front and center. 3)It is a stable platform, unlike Origin and Uplay (constant crashes in both systems for me, causing the game I was playing to close.) Crashes can happen (like in any game system), but are unlikely. 4)This pushes BNet into a competitor for Steam, which it sorely needs. Valve has been sloppy with Steam as they really do not have one. This push might actually get them to innovate both systems into something better. 5)Its not the Windows Store.

Cons: 1)Its not Steam and, even with Overwatch and WoW's popularity, will not be the same amount of traffic and will affect sales. 2) When Blizzard's authentication servers are down, there is no way to jump into the game. Lesser issue since Destiny 2 is an online game but if the game is supposedly up, you would not be able to jump in if BNet is down. 3) BNet is no where as developed as Steam with its community features, friend's list, sharing options, and modding system. Blizzard tries but having a community who is willing to play artist or developer for free is something that can keep a game running for years.