Some of the disadvantages of bitcoin are as,
- Government can be ban on bitcoin, and force merchants for not use it.
- Always there is fluctuation in value of bitcoin.
- As it is virtual cryptocurrency, it is totally depends upon internet. If in case internet get off then thats create major issue.
- Also there are chances of lost of wallet in case of viruses corrupt data or hard drive crashes and wallet file is corrupted.
I agree for 3 thing that you mention above as disadvantages of bitcoin.
In no2, always fluctuation of bitcoin value is double face depend of each people.
I mean fluctuation of bitcoin is advantage of bitcoin. Why? As trader i get profit because of the fluctuation.