Most places on the internet have at least a cultural hostility to "self-promotion", which includes any linking to one's own content regardless of how relevant or useful it is. Some places have an outright rule against it.
Here's a rule of thumb: if the only reason you can come up with to oppose something being linked is the identity of the person linking it, then it's appropriate content to link.
Rules against self-promotion are not just misguided but generally harmful. They make it much harder for new creators to enter a market. They make it a huge catch-22 because you can't get exposure unless someone else promotes you, and without exposure, there's no one to promote you.
I might overestimate the strength of the taboo because back in my years of folly when Protagonism was severely under-refined, I ran a Blogger blog and got censored several times for promoting it. I haven't been actually censored since yujiri.xyz because I'm a lot more reserved about linking it, so I don't usually try risky stuff. But the taboo is definitely still there and doing damage.