In China there's a lot of big coastal cities with very little open land for development. Putting small amounts of solar onto 1000 skyscrapers vs one big ocean plant, and the additional costs of ocean maintenance start to be less significant.
Similarly, in some places there may be opportunities to align the deployment of the panels with other systems, e.g., a kelp farm or ocean fish farm where you can collocate ocean structures.
There's likely to be lots of new challenges faced by these structures, but it's still good to work the kinks out now with some pilot projects