The Bo 105 started aerobatics in the military as well. But as the military can do what they want with their assets you could even use a Huey if you liked😉
Of course the RB helicopters are the only ones with civil certification. This is what counts. And there is no other manufacturer to date to have certified one of his (rotary) products for aerobatics!
This implements - there might be others who CAN do it but only RB is ALLOWED to do it🤓
By the way - with all the maintenance restrictions for the certification RB estimates an aerobatics flight hour for the Bo's with 36.000 Euros!