I never new about gradual engagement until using the stripe website. In this case it worked for them and I continually added information into my "guest" account until it was my full fledged account.

This might not work for all web services, but I think it works well for stripe. I honestly doubt I would be using stripe today if they didn't have gradual engagement. When I was in the market I found stripe during my "research" mode. I stumbled into their site and as I "learned" about their product I was also "building" my account. In the end I felt little friction and I integrated stripe payments into LinkPeek.

tl;dr Gradual engagement success appears to depend on the type of person or market a service targets. Pulling from BCC we could deduce that gradual engagement may not work well for teachers, or that your implementation did not work well. I know from experience that this technique converted me from a spectator to a consumer. My personality might not be typical but I generally don't like pressure and often have a bad case of buyers remorse after making purchases. I didn't feel this when "researching" on stripe and I ended up a customer.