8 – How do I, as a module developer in D8, handle the output of custom strings in terms of translatability?

A module I'm working on introduces the ability to customize some messages that are output to users on the site. Previously, messaging was hard-coded and output using the command TranslatableMarkup Class. I now allow these strings to be adjusted in the configuration.

Is it still appropriate to just save the code that contains the configured string Translate Markup Class? It seems like I should not do that.

I have found this old core issue that seems to be related to what I'm talking about, but there is no clear conclusion on what to do.