A qualified "yes".
It's just a part of the decomposition process that the stuff would go through if it were being used for compost.
The qualifications are :
- it depends what you are planning to use it on, as to whether or not it may adversely affect plants.
- personally I would not mind using it on open garden beds but I might hesitate on using it on a kitchen garden in case there were some spores likely to spread to edible plants
- if it's already starting to break down, it may begin to draw nitrogen from the ground to complete that process
- it may need to be turned a few times otherwise it could pack down and block rain/watering penetration
- YOU need to take precautions if you are handling it to avoid inhaling or ingesting anything nasty (remember all the warnings on every pack of potting mix!), so, mask, eyewear, gloves, and make sure your clothes go to the laundry, and you to the bathroom before you eat, drink or be otherwise merry

Sugar-cane mulch! I use it all the time, I buy it - 4 bucks a bale - from the (sugar-cane) farmers in the Tweed Valley around Murwillumbah. It's light colour helps to reflect the summer sunshine heat and on breaking down it releases some nitrogen into the soil. Good stuff. Oh, and yes, as Alison says, good idea to wear a mask, especially if it's dry. I gotta admit, I don't and should.
B.