That layout goes against usual touch typing rules.

https://upload.wikimedia.org/wikipedia/commons/thumb/2/29/To...

As you can see the rule for the left index finger is: 4 R F V, but the keyboard you posted suggests a layout: 6 T F C

The latter layout look appealing, and I wonder why is touch typing using the former rule, since it makes both right and left hand move on a right diagonal instead of right-right, left-left.

At a first glance none of them has any visible advantage.