Do you have an XL or the standard Pixel 2?
If you have an XL then I don't think you have to worry about that at all. The battery is a beast, and Oreo has improved battery life over Nougat.
Unless you're a serious power user with 5 hours of screen on time or more, the battery draw of Now Playing will simply be a non issue.
It's probably the same way with the smaller Pixel 2, I just can't comment since I have an XL.
Thanks, I have the regular smaller Pixel 2. I'm going to leave it on because Im not a power user.
Its another feature I really like.. hope you are enjoying the XL
Cheers