You can certainly meter using another camera, but it can be cumbersome, mostly because the camera is significantly larger and heavier than any meter. A spot meter isn't a requirement.
OTH, if you will generally have the other camera with you any time you're working with the Hasselblad, and, you're using the same film in both, it may work out for you.
However, in switching back and forth, if you're used to eye-level viewing, and if you're likely to be working with a 35 or digi kit along with the Hasselblad most of the time, you may want a prism on the Hasselblad anyway. Otherwise you may go nuts adjusting to the reversed view in the WLF every time you switch cameras.