I don’t totally agree with you that mental rituals are more effective. I think they are the same thing in the end. They may seem more practical, but mental rituals require prolonged intense concentration, that can sometimes be replaced with a simple object.
We are currently physical beings. I don’t think there’s any way to escape that. In such, our consciousness understands physical actions and symbols.
I’m not against purely mental rituals. If that works for you, use it. It’s a very Eastern approach.
I am, however, a Westerner. I was raised that way, and I think in Western ways. We in the West are materialistic. Our magick tends to be much more materialistic as a reflection of the culture. Take alchemy, It is an entire system based on the metaphor of transmuting material things.
In essence, both are ways at getting at the same thing. They both have their advantages and disadvantages.