They are thin-film technology which, by the manufacturer's own admission is less efficient than the equivalent standard crystalline PV panels. So depends what other drivers (e.g. appearance, lifespan etc.) are important.

From the website:

"The CIGS laminated solar modules will produce approximately 135W/m2 which is lower than monocrystalline panels, but the low light performance and higher possible roof coverage means the expected output can be the same"

Others on here will be better versed in the figures, but I think you can get premium panels that offer 200+ W/m² now and you'd have the flexibility to swap them out (rather than the bonded panel Solarseam).

Seems like it's geared to areas where visual restrictions (e.g. conservation area) can justify the presumably increased costs.