Watching Movies is not a sin.
Movies are highly beneficiary. They are agencies for sending messages. You can imagine, it is through movies that we are able to listen to the teachings of Bro Eli Soriano here. We didn't go to where we were able to see him preach face to face. We weren't in the congregation where he was teaching. But we have been blessed with the lessons through listening to these videos.
Movies are knowledge packs. We learn from videos. We could acquire knowledge just by listening to the movies. So watching movies couldn't be sinful. We can learn great lessons of life from the videos that we are watching. So, movies can be classified as means of transferring knowledge.
The issue about movies is that we should be cautious when we are watching movies. We should not allow ourselves to be addicted to it. The pleasures involved in watching movies should not control us. If we allow movie watching to influence us wrongly, that is when it will become sinful.