Reply limit in the mailing list mode?

I got this after replying to an old thread via the mailing list mode.

Email issue -- You are trying to reply to an old notification

We're sorry, but your email message to didn't work.

We only accept replies to original notifications for 90 days. Please visit the topic to continue the conversation.

where "90 days" seems to be configurable, according to discourse/server.en.yml at 6b7bdc991d9912c4fc4da879f7c9689a528ed35e · discourse/discourse · GitHub

Does anyone know the reason for this limitation? And if the limitation can be removed, does it make sense to do it?

I've removed the limit.