There certainly is a danger of monopolization with chrome garnering an overwhelming majority of user share. However, I'm yet to see the negative in testing with

There certainly is a danger of monopolization with chrome garnering an overwhelming majority of user share. However, I'm yet to see the negative in testing with chrome and shipping (assuming you're only using W3C APIs), as most of the time, chrome is fully compliant with W3C, and other browsers simply aren't. Apple is the worst, most guilty of the others, that purposefully cripples iOS Safari to goad users and developers towards the app store. Microsoft probably intended to be fully W3C compliant with Edge, but for whatever reason, they always lagged. And with Mozilla/Firefox, it's always an obtuse, unreasonable argument when they don't comply, they claim it to be in the best interest of the open web, but it is usually a philosophical, more than technical opposition.