(Although I'm hesitant to put a pihole up there too, it would not be the 'official' pihole or maybe in a container, both don't seem optimal).
But what I meant is: From a practical standpoint, on a daily basis, besides your subjective feeling, nobody else notices a difference if your router has Vim or not - as long as it works. And any decent router nowadays usually works.
And I think one should realize that this is tinkering for the tinkering's own sake. There are no objective benefits[*] if you ask an outsider, e.g. your partner.
And now I have to manually keep my router up to date, against all possible bugs in numerous open source packages. In 2021 at least security updates should be automatic for OSS- period.
[*] (Repeating:) UNLESS you have some specific requirements, e.g. VPN, multiple uplinks, specific software due to specific use cases, etc. In these cases OpenWRT/Tomato etc. are an somewhat easier and cheaper way to get your own stack running, compared to setting up a full-fledged OTS x86 box with Linux or BSD, even pfSense is more work and more expensive I would argue, where the benefits over OpenWRT are even less tangible.