If you have a lot of meetings with external parties (it's not about scheduling between the 3 internal) a good calendar scheduling tool is worth it in my opinion. When I was a sales engineer at a software startup we probably spent 10-15 minutes per lead sorting calendar times out. Considering only 1 in 10 leads turn into sales this was 2.5-3 hours per converted lead.

By having a self service scheduling tool we already filter for the non serious people "I'm not wasting my time finding time in your calendar" and improve our lead quality while reducing the back and forth nonsense that no one enjoys.