Saying that Bitcoin is well adopted is a bit too generous, considering that you can't just go outside and spend it, and you have to specifically look online for the closest places that accept Bitcoin, and then spend potentially a lot of time getting there. And even online it's hard to spend it, because big platforms like ebay or Steam don't accept it.
With a marketcap of over $2 billion, why the reason PayPal want to included as ones of the money they are accepting for payment why using their platform? I think that answer the question.
In no way does Bitcoin solve the problem of theft. Not only it can be stolen physically, if you have a paper wallet, a seed phrase, a digital medium with an unencrypted wallet file, it can also be stolen digitally via hacks, phishing, malware, etc. For people with poor security practices, which is the majority of the population, Bitcoin theft is a far bigger threat than some bank theft.
That is why people should be security concerned, if someone is security concerned, it will be difficult or impossible for hackers to penetrate, there are many ways to avoid these, like generating your private key offline and also having strong security against hackers. Prqctically, you are right, that is why people need to be conscious digitally.
One important characteristics of money is that it is generally accepted by every one in the community or society but bitcoin is not yet known by all the people. Bitcoin is still struggling to go to people's accepting it, it is still very volatile and money isn't. I think that we can look bitcoin from area that it is digital currency purpose.
You are wrong, bitcoin is accpeted by people, that is why its realized cap is increasing, which society does not accept bitcoin when it is even used in countries that ban it, while most countries legalized it. Is it volatility that also matters or depression? Fiats are just depreciative assets while bitcoin is appreciative in nature. Bitcoin is a successful currency already.