There might be cases where it could be useful, but most of the time there’s no point for a pinned topic to stay visible all the time if we have read it and the information it provides was registered.
I use some old-school forums (phpbb and vbulletin) that have a handful of useful pinned topics I’ve read years ago, and I’m so unhappy they constantly stay in my face that I use a custom client-side CSS to hide them (plus the whole thing takes lot of room that could be used for regular topics, especially on mobile).
I’m happy about Discourse’s choice regarding pinned topics behavior, as it makes more sense in every ways.