There is interruption, only it occurs during hashirama's chase.

There are so many ways to use hashirama and sage. Because of his passive healing whenever you get chakra, you c*e him as a sustain tank, it's especially nasty and annoying to play against if you pair him with water main (chakra absorb) or any other ninja with that passive- snake kabuto, jigokudo, danzo. Personally my most used team is mei, sage, hashi and fire main (44221 dog of hell). Most of the time his barrier isnt win condition, it's more of an interrupt bait. You can substitute mei with pretty much any ninja, either support or damage dealer (when the other ninja is a dps, your main fulfills the support role), that ninja doesnt have to be konoha if he provides enough value to be good on his own (see: mei).

Hashi can fulfill several roles: buffer, sustain tank, cc machine (paired with bee or after 2nd skillbook), barrier breaker. See which of those roles could help you the most during everyday play and build accordingly.