We can do this but that it won't work. For example, sat we have:
`VectMul(scalar, VectAdd)`

Then, the VectAdd isn't necessarily in just in one coordinate system. For example, `e_x + e_phi`. That's why we don't have this. I am currently facing this as a problem (having vectors from different coordinate systems in a VectAdd) and so, I am writing a few helpers that would separate the vectors in different coordinate systems.