Yes, BLADE attachments are not very safe because --unlike a proper chainsaw-- they don't have a brake that disengages the drive in the event of a kickback. Likewise there's a lack of a trigger switch as you already mentioned is a problem.
The DISC attachment apparently is even worse! The report states that chainsaw discs attached to angel grinders have caused several catastrophic injuries to face and neck areas. Apparently the entire contraption can propel itself upwards when kickback happens.