Case: Let's assume there is a significant lead time from a conversion on the web until activation of a service actually happens. After activation and as a part of the onboarding process for the service you want to not only use triggered emails/texts, but also expose the visitors for relevant content online (the full omni experience and all that).
Any smart feature in Target that will start exposing users n days after they qualified for the base segment?
Yes; I think (in theory) its possible to use recency on the trait(s) within the segment e.g. has qualified for the trait equal to or more than one time in "recency > n" days to obtain this, but any built-in feature would be preferrable.