It's not just a Chrome-, it's a Google thing. If you want to install F-Droid or Exodus on Android today, you have to get past Google's warning that you are putting malware on your device.
To be somewhat fair there, side loading an app should really have a giant warning, otherwise it would be really easy to trick less knowledgeable users into installing actual malware. It would be nice to have an easier way to install third party app stores, but to install an APK from a website/browser really should have a giant warning.
Worlds better than the competition that outright bans side loading other than a weird "only x number of apps" and "must reinstall every x days".
I mean, they've already started cutting some features I have used... So I've got Firefox and Pale Moon on my PC to cover the loss of ftp support. And since some pages don't work in Firefox in either instance of engine, I have to have Chrome installed...
It genuinely sucks that some websites don't bother to support Firefox! When you encounter one, you might want to complain to the devs and open a webcompat issue.
So it's like that thing the Internet Explorer is Evil! website complained about back in the day, but now instead of Internet Explorer, it is Google Chrome...
I have already encountered some websites which didn't work with Chrome very well, but did with Firefox. They mentioned it's because of how Chrome now handles audio, the audio doesn't start.
I mean, it's not great, but it's also not the worst. You can also disable it. Chrome gets money by collecting your data to use for advertising purposes. Firefox doesn't do that, so I don't see much harm in them advertising some of their products a couple times a year. Even wikipedia advertises their own donation period, trying to encourage users to donate.
If it were a persistent banner, that would be different. But a one time closable window, that can also be disabled, is really not that terrible. Companies need money, after all.