4yr old procrastinator

So my son has always procrastinated so much for naps and bed. He calls us into his room multiple times just to talk and sometimes bedtime can last hours. We have the "talk" function on our monitor and he hates it. He says it scares him if we talk on it. We've used it a few times and he won't make another peep after and goes straight to bed. We always go in his room at least 2 times to make sure he doesn't actually need anything and then warn him "next time we are going to tell you to go to bed on the monitor". He usually goes straight to sleep. I hate scaring him but it's the only thing we've found to work. Do you guys think it's bad or would you keep doing it if it works?