On very rare occaisions when I am using a multiple studio strobe setup, I will use a light meter to get through the setup faster (positioning light modifiers, setting power balance between the strobes). But otherwise the in camera metering does all that I need and does it quickly and well and doesn't require much thought (because Canon put a lot of thought into the design of their system).
Rodger
EOS 1DX M3, 1DX M2, 1DX, 5DS R, M6 Mark II, 1D M2, EOS 650 (film), many lenses, XF400 video
