You need to keep in mind what an EBC give you. Aside from the ease of changing settings, it also gives you more features. It allows you to store multiple settings into different channels and switch between them. They also replace the factory solenoid with a higher performing unit. A dual solenoid can operate a lot faster than the stock one and it would give you much smoother boost control. You also get things such as overboost warning/protection, scramble modes, peak hold, and in some cases data logging.
For me, those factors were enough to justify getting an EBC over a MBC. In addition, I really don't feel like getting out of my car to adjust it. . even if it is only once or twice a week. Everyone has their own preferences. If you want to save money and go for an MBC, more power to you. I chose to get an EBC. I didn't feel it was a waste of money. Some people spend $1000 on a body kit, which I feel is a waste of money, but that's my opinion.
The main point is that you have to do the research and decide what's best for you.