I would like to add my voice in favor of relative internal links. I currently use full URLs to reference, for example, another topic on the same site.
Indeed, our site recently switched domains (noting that redirection is currently active):
And our new host, Communiteq (formerly DiscourseHosting), kindly somehow sedded our database to reflect this change.
Maybe there are technical reasons for the current status? Maybe we can use something like %{THIS}/t/000 in the future? As a developer, absolute paths usually make me nervous. There is also the question of switching from http: to https: which we also undertook (or at least enforced more strictly) as part of the aforementioned migration. This looks like much the same use case as @mreach
As always, many thanks to the discourse team for a wonderful product. R.