Well, the question is where you draw the line of being “insecure”. Fact is, it is way less secure than Chromium and in a browser this should not be taken lightly. I would not call it secure enough for the average user who clicks on every link without thinking twice. And I agree with Job Choice:
“I really believe that if your infrastructure can’t survive a user clicking a link, you are doomed. I’m the director of cybersecurity at NSA and you can definitely craft an email link I will click…” and “Clicking is what links are FOR.”
Browsers have a different threat model than OSes protecting against malicious apps respectively RCE+SBX of apps. It is more likely to visit a website containing something malicious than installing a malicious app from the Play Store.