Still grokking, but one question that comes to mind is how does the MEVM process Messages []core.Message as the naive way of processing each individually would inhibit onchain atomicity between messages I believe?
This may not be a large concern though, and the reason for that is additionally why I am beginning to be in favor of this approach: you can replicate the old approach within the new approach.
But overall, if I am understanding this correctly, then I am a fan! The parentSuapp example is particularly motivating.
On UX: side effects was an initially confusing term for me, could we call it something like request_state_update or trigger_state_update? This would fit well with our internal thinking about multiple different states within a kettle, the two most obvious being local and global. Actually, an even cooler idea, perhaps we could eventually have multiple “DA layers” (slight term abuse sorry) and you could chose which is updated via your side effect/update!