Disclaimer: I'm the CEO of urlscan.io
1. To bypass your corporate proxy (ok, not the best reason);
2. urlscan also allows you to pivot easily and find the same phishing kit as they have a nice database of scans;
3. urlscan also allows you to see the website from different proxies, which can be useful if there is geofencing.
It isn't that simple and threat actors are far from being dumb :)
Edit: even better, every tab is a separate container instance, i close tab, it nukes the container
As for improving on tab isolation over what existing browser sandboxes already offer, lightweight virtualization a la Firecracker seems like a more useful increment than containerization, and, assuming each tab has a similar VNC-like connection to its browser VM, virtualization would also make the whole "throwaway computer" setup less necessary to provide a meaningful security improvement.
https://nvd.nist.gov/vuln/detail/CVE-2023-3079