Bitcoin to me represents a thought process and it's that thought process and it's impact/ramifications on society that makes it so popular among the people who understand the underlying technology behind it.
So let's try to understand what changes the blockchain technology can bring about.
Power and control back to the people - The blockchain technology removes the need for the middle man because it uses technology to create a trust-less system and this bring control back to the people.
Eliminates possibility of Fraud - Because a blockchain is immutable meaning it can't be tampered or changed, it removes the possibility of Fraud from any transaction.
Transparency - Since blockchain technology used decentralized public ledger it's totally transparent.
Privacy and Anonymity - As long as the money that I have is my hard earned money and I have paid taxes on my income, it should be nobody's business to know how much of it I have, where and in which form I keep it and what I do with it. This is what the blockchain technology makes possible.
Ease of use - By having my money in the form of bitcoin/cryptocurrencies, I am practically my own bank. I can go anywhere in the world without having to go to money changers because Bitcoin is like a global currency. Cross border payments can be done in a matter of seconds without the need to pay huge fee. Imagine how this will help grow cross border trade and business. Use of cryptocurrencies for payments would make life so much easier for customers as well as merchants. No need to visit banks/ATM's to withdraw money, no need to use credit cards ( which only holds banks make money).
Now coming to why the governments and regulators are scared of it. It's very simple. The blockchain technology is designed to facilitate peer to peer transactions making third parties redundant. Who would want to lose control and power. Thinking objectively, the work of governments should be defense, foreign policy etc and not bothering about what people do with their money. It of course is desirable that government around the world come up with regulations so that cryptocurrencies are not misused for carrying out illegal activities and to protect investor interest from frauds and scammers. Forward looking and progressive countries are doing precisely that.
So to summarize Bitcoin has just brought about a change that has the potential to change the way the world works, just like the internet did 20 years back.