Elementary is aimed in part at non-power-users, moreso than most other distros besides Ubuntu. Most of them don't care or even know what browser they're using.
So yeah, there's definitely a value IMO. In fact, I know for a fact that my mother in law has been using linux for years because they just set it up for her and installed whatever she needed to get stuff done (libreoffice, zoom, whatever).
To that end, why not just go with Firefox, which would appease the more technical users, would be closer to what most other distros out there are doing and would also have a higher chance of it being familiar software to all users?
I think that for the most part custom browsers are only good when you want to include something functional, yet minimal in your distro and want to save space or something like that.
Edit: admittedly, an argument could also be made about having software look and feel consistent with the rest of the OS, where such a solution could be better than off the shelf browsers, at least without heavy modifications.