I did a cycle of the starter cubes to root cuttings and did not like them. oasis cubes, rockwool, peat pellets, and aerocloning worked have better for me.
My bud ran a few of his ebb n gro buckets with STG and saw some algae growth on the top.
I dont run DWC so I cannot comment on that,.. can only speak from my past experiences.
I'm sure they have a useful application somewhere. Just doesnt suit any of my needs... Different strokes for different folks, I guess