The Tester Approves thread (see first post)

That bike24 description says 'not for ST levers'

They're obliged to conform to a strict interpretation of the Shimano compatibility chart. In practice, they're fine if properly adjusted. I think the shorter total lever throw of STIs (because the gear lever hits the bars) means that if you set up the initial pad clearance at the maximum permitted, you might run out of lever travel before generating enough stopping power to pass the deceleration test.