I have been following Form for a little while. There are big challenge in the 'rust' gumming things up and limiting the cycles. I kinda view this with all the other battery breakthroughs.... I am not going to hold my breath. Don't get me wrong, I really hope they succeed but I have been disappointed too many times to get excited before they are 'real'.
Note: One thing I do agree with is that in the long run Lithium Ion may not be the right solution for grid energy storage (For all the reasons the video talked about). The scale of the grid storage problem is such that something fundamentally different than lithium ion is needed. It is going to be all about $/KWh and the Weight and Energy Density advantages of Lithium Ion can (mostly) be ignored for grid storage