Ads have never bothered me too much, on certain sites I'd let them run even if I could block them (to support the site) and if a site is really that riddled with badly covered ads I'd just end up avoiding it...
Initially (with the first 3 HTC EVOs) I rooted for the customisation aspect and ROMs, but I'm over all that and even stock Android has adopted most of the early mods I really digged. I rooted my Nexus 5 mostly for free tethering (on Sprint) and Titanium...
Helium can be a suitable replacement for sync'ing game and some app data without root (what I used Titanium for), and most newer plans/carriers no longer charge extra for hotspot tethering, so I doubt I'll root my Pixel, never rooted my Nexus 7 either.
If you're considering it and don't know where to start my best advice is this: don't take shortcuts, don't use a toolkit unless absolutely necessary for your phone (not necessary for Google devices), and don't run around asking for advice right off the bat.
READ, research, figure or anything you don't understand, start experimenting (maybe ask questions then if you're really at a loss over something), and then read some more. If you're not willing to spend a few hours doing that (yes, hours), running a rooted phone really isn't advisable for you IMO.
May sound harsh, but it's just brutal honesty.
P.S. Even tho I rooted my N5 I basically kept it on the stock firmware and even the stock bootloader, so I could take OTAs... Not quite sure if that's possible or even advisable on the Pixel with the new partition system.