Google Flights' list of booking options is much more reliable and trustworthy than the sketchy OTAs that offer slightly discounted flights and then conveniently disappear with your money if you ever need customer support, or worse, levy bullshit fees to do things that would otherwise be free if you booked through official channels.

If you want to screw yourself over for $20 savings, use another flight search engine. I'm quite happy with Google Flights myself and don't need it ruined.