Can a pram bassinet be used for overnight sleeping? If not, what are the dangers?a

Product Safety Australia & Red Nose do not recommend a pram as a sleep environment, particularly overnight when not supervised, as they do not have standards as sleep environment.

Avoid sleeping children in prams or strollers…....If they are asleep, maintain regular supervision.
https://www.productsafety.gov.au/standards/prams-strollers

Never leave your baby unattended in a pram or stroller. It is not a substitute for a cot
https://rednose.org.au/article/prams-and-strollers 

Raising Children Network has the following information
If your baby falls asleep in the pram, either watch him or move him to a cot. It’s dangerous to leave a child unattended in a pram or stroller, even when he’s asleep. He could wriggle and make the pram tip over. This could lead to suffocation or strangulation in the pram’s folds or gaps.
https://raisingchildren.net.au/babies/safety/equipment-furniture/pram-stroller-safety

While there are no standards in Australia for bassinets, Product Safety has the following information.
Ensure the sides of the bassinette are at least 300 mm higher than the top of the mattress base.
Ensure it has a wide stable base and a sturdy bottom so that it won’t tip over.
Ensure the mattress fits well and is firm, smooth and no more than 75 mm thick.
If the product has folding legs, make sure it cannot accidentally fold during use.

The most common reports about bassinets (& prams used as bassinets) are in relation to falls & suffocation