Bringing up the age old comparison, from the explanation you gave it just sounds like how Homestuck is formatted... a drawing showing the scene but the dialogue/exposition/Words being underneath it in a chat-based format.
It sounds interesting enough (and if it worked for homestuck, well...) I feel like it's really up to you on whether or not you think it'll be an appropriate method to tell your story. Certain methods of story-telling can work best for a story while others can hinder it, but it's really up to you on whether or not you think it'll be an efficient way to tell your story.
as for me, I'm probably not gonna use it. I like drawing out my comic pages and a character in my next story is mute and expresses himself through his body language so....chat format won't help much.