NSW BDM issued death certs (or official transcriptions) have sections where the information MUST be accurately recorded ..... Cause of death, duration of illness, how the body is disposed of, where and when .... As a direct consequence, you can confirm the cemetery or crematorium, sometimes the denomination, and also look for possible inherited diseases etc.
The information that is often considered "questionable" is that part of the dc that names the informant's family history. It can be flawed, but the person providing the information is required to sign a statement showing they believe it to be true. As that informant is often a family member, it is information given at a time of grief, and is usually given to the funeral director at the same time as the arrangements for the funeral are being made. Thus the family member providing it is often more concerned with those arrangements, than with the questions about the deceased's family history.
From my point of view, it can be worthwhile working towards obtaining the dc, if only to see who was named as the parents, or the spouse/s or children by the informant. And from that to start to consider how well the informant knew any of the family. For example, (names changed to protect the innocent !) Freddy BONKERS died in NSW in 1938. His dc shows he was married twice and that the informant (Johnny, ie Freddy's stepson from the second marriage) did NOT know the name of the first wife, nor if any children from that first marriage.
In fact Freddy BONKERS had been married THREE times in NSW. First marriage produced at least 4 children, and the wife No 1 died in childbirth. Second marriage was to next door neighbour, a widow with 3 of her own. The second marriage for Freddy BONKERS produced 2 more children, and wife No 2 quit leaving Freddy with those 2. Freddy obtained a NSW divorce, citing a co-respondent. Freddy moved several streets away, and then married a divorcee. Mrs Bonkers # 3 died several months earlier than Freddy. Her son (Johnny, the informant on Freddy's dc) seems to have got all of HER details down fairly accurately on her dc. But not Freddy's ....
But the headstone on Freddy's grave does note ALL his own children from each marriage.... They are just NOT noted on Freddy's NSW BDM dc.
So, there are advantages to seeking out dcs where the civil BDM regulations extend to providing certified information that goes further than just the registration of a death...
So, the amount of information on the dc depends on the regulations applicable for the state/territory where the death occurred. So for example, England & Wales certs have very little info, but Scottish certs are detailed. South Australia's certs have very little information but Victoria, NSW, Qld, WA are detailed. As an aside, Victoria's certificates are perhaps the most detailed in the whole world.
Cheers, JM