Per HMNY's SEC filings, in Q1 their total cost of revenue was $136 million. Revenue from subscriptions was $47mm.
So that gives us a range of impacts.
If all these people would have not gone to any movies if there were no MoviePass, it was a $136mm boost to box office in Q1.
If on average these people would have spent the same amount of money to see movies, but saw 100% of the "extra" movies they did above that cost thanks to MoviePass, it was an $89mm boost to box office in Q1.
If on average these people would have gone to half those "extra" movies anyway, and just enjoyed the deal they were getting, then maybe it was a $45mm boost to Q1 box office.
That's roughly the order of magnitude we are talking about, in Q1. Q2 hasn't been reported and I guess might never be...