Yeah, anything using perovskite but not mentioning on how they intend to keep the cell from degraging is likely just gunning for top performance. Like, gunning for a land speed record will not net you a perfect commuter car. Still, it is encouraging to see progress in the field.

It's a record for this tandem combination. But it is still not the best record for a tandem configuration. As for costs and durability, separate issues as noted. But progress.