Wow, what do I read? Festool has different heads for years now and nothing but praise for the added functionality, and people keep asking for more different heads. Bosch now does the same thing and adds one extra head and "suddenly" they're a jack of all trades but a master of none.
How typical of some in this crowd.
As for the power of the SDS head, of course it's not that powerful, it's only a small 14,4 volt drill driving it. But if it can make holes up to 10 mm, most jobs in and around the house are covered. Would be ideal for me, I don't encounter much jobs where I need a full SDS drill, but sometimes when I do, an attachment like this on my T15 would come in very handy. And my T15 is not just for the "nice" jobs, it's for every job that needs some precisely dosed rotation.