May make it easier to customize but it doesn't close the security loopholea like SELinux, GRSecurity, TOMOYA, or AppArmor does.
https://www.cyberciti.biz/tips/selinux-vs-apparmor-vs-grsecu...
Now for many that threat model is not sufficient as they both run increasingly less trustworthy software, obtained by less trustworthy mechanisms such as npm or off a website, or simply want to protect against bugs that cause otherwise non malicious software from being compromised and resulting in security incidents. I'm in this latter camp but we can't ignore the fact that there are many who happily operate in the former. There also exist solutions such as we browsers with their sandboxes and VMs that somewhat fill the requirements for running untrusted software for these individuals.
Which is a fanciful way of saying that I don't understand the relevance of your comment at all to the topic at hand, which is an interactive frontend.