1) While Bitcoins are not controlled by an actual Government, etc, that also means that there is no official "customer service" for Bitcoin, especially when it comes to reimbursement; If you lose your private keys you are screwed, the coins are gone and therefore your money. Doesn't matter who you buy Bitcoins from, they can't help you at that point. Some companies have made this pretty avoidable though, by just allowing a username and password to sign into your Bitcoin wallet.
2) Not enough businesses directly accept Bitcoin. While some big name companies do accept them, overall they aren't accepted at most online and local businesses at this point of writing. There are a lot of ways around this though just because of what Bitcoins CAN buy, which can be used to trade for the item you desire. For example if a local or online business accepts PayPal but not Bitcoin, it's easy to convert it.
3) Bitcoin can be stolen through malware, social engineering, being robbed at gunpoint, etc. Malware can certainly be avoided, you can store your Bitcoins offline, encrypted, etc. on a malware free machine/device. Social engineering is unlikely, if you are familiar with Bitcoins, you are probably familiar with social engineering. Being robbed at gunpoint can hopefully be prevented by meeting in a busy coffee shop, etc.
4) Bitcoin is not "user friendly". With terms like "Blockchain", "mBTC", "Private Key", "Hashing", "QR Code", etc. I can see where a lot of not tech-savvy people would be discouraged. It's clear that Satoshi didn't design Bitcoin to be used by everyone.
5) You can't pay your Government's taxes, fees, etc. in Bitcoin (at least I know in my country you can't).
Feel free to contribute to this, I would love to hear some opinions.
1) If you lose your cash, they are gone. No one would care if you lose your cash too.
2) Bitcoin is considered a much better alternative than Bitcoin, businesses are reluctant to accept them due to waiting time, acceptance rate and price volatility. The last two can be solved by Bitpay while the first one can't be solved unless Bitcoin's max TPS can be increased. Some business like Bitcoin due to the un-reversibility and low cost.
3) Your cash can also be robbed at gunpoint. Bringing only a small amount of Bitcoin for meetups would largely prevent this.
4) Bitcoin apps are designed to be as user friendly as possible. An average joe would only need to know about confirmations, prices and addresses. It is quite easy to learn.
5) Government aren't that open towards Bitcoin due to the possible risk of money laundering and terrorist financing.