For stills, not so much, considering the cost.
For anything cinema, yes -- please. It drives me nuts when the light of a set works with F/2.0 or F/1.4 or T/... for that matter (filming on location in, e.g., a bar for a music video and no budget for light) and then no way to go wider.
I guess to make that happen, we would see easily a $4-$6K figure for that, which might be more of a prestige object for Canon than a good sales investment. Just a wild guess.