The left turn issue isn't much different than for any other bicycle side path if you think about it, which is another point against side paths in general.

I think this design may have some utility at busy intersections where there are large numbers of right turning cars, but at $1M per, may not make much sense. Care will also have to be taken o make sure the islands leave enough turning radius for long trucks and buses, so the entire intersection may end up using more real estate than otherwise.

The irony of all this effort to cater to the so-called interested but concerned is that once they start riding, many will come to dislike the new features that were made for them.