I absolutely love the idea behind this.
Plastics in our oceans is so damaging to marine life, and directly to us - with micro plastics making their way into the food chain.
So anything which promotes cleaning up the oceans, or at least stopping further dumping (or helping to) of plastic is on to a winner.
And what an amazing idea, to make construction so easy. I'm sure there must be more to it than meets the eye (with building regulations, etc.), but it's a great concept.
The one thing which does concern me, though, is the pollutants within the plastic bricks. I'm sure that plastic, in large quantities, is not a great environment to live in - when you're surrounded on all sides by it. Hopefully, as part of the recycling process, they remove toxins and harmful elements, which may affect health.
It would be so good to see this technology take off, and become widely used and accepted as a building material.
Great hunting :)