Well, it's not a significant amount of new plastic on a global scale. However, why does it make sense to spend gobs of money on something that at best won't help and at worst will make things slightly worse? Why not invest in proven strategys, like bag bans or trash collection around populated rivers and bays? An example of this is the Baltimore trash wheel cleaning up the bay. It's cheap and effective, because it cleans up garbage when it is:

a) Not broken down to be microscopic. b) Concentrated.

I should also point out that they claim they can finance a big part of this by recycling the degraded ocean plastic. I shouldn't have to tell you that that is absolutely whackadoo.