Gmail Ads - worth it or not?

Anyone had good experiences with Gmail advertising?
Just wondering if it's worth looking at for affiliate marketing / list building...
I'm starting with a skeptical mindset because I almost never open Gmails in the Promotions tab, but that's just me.

As a followup: if Gmail ads do work - any tips on how to get best results?

Please share your pearls of wisdom - I'll be very grateful!

You know it works if you constantly see businesses advertising there.

Damn, even people out there think traditional advertising doesn't work, yet we have huge corporations spending billions a year just to grab your attention. Gmail promotions are just another avenue to get an opportunity to have people's attention.

I have never clicked on a gmail ad but someone must be clicking on them because people keep advertising there.