Well, i thought that since I did not download any extra software on my system, never click on unknown links, and had an updated anti-virus on my system, so it is hard to get any malware on my system.
Hard? Maybe. Impossible? Absolutely not.
How can you be
sure you'll never click an unknown link? You can't. How can you be
sure your anti-virus will pick up every possible piece of malware? You can't. Where as I can be 100% certain I will never click an unknown link on my airgapped computer, because it has no hardware in it which is capable of connecting to the internet.
Also, another thing that made me confident of my system is that i haven't faced any such issues for the last few years, using Electrum as a hot wallet.
This is like saying you have driven for 5 years without wearing a seatbelt, so you are confident you don't need a seatbelt. Just because you have been safe so far doesn't mean you will be safe forever more.
Anyhow, reading all of the replies and none agreeing with my point of view, i have started to feel scared.
Hot wallets have their place. I use a hot wallet frequently. But I only use it for amounts I can afford to lose. My rule of thumb is "How much cash would you carry around in my physical wallet?" $100? Fine. Then $100 worth of bitcoin can be in a hot wallet. $10,000? No chance. So that amount of bitcoin should be on something more secure, be that a hardware wallet or an airgapped wallet.
Since i do not have any extra system with me right now to meet this emergency, is the tails USB with the built-in electrum can be trusted?
It's certainly better than a hot wallet, provided you disconnect your internet connection prior to booting to Tails and keep Tails offline the entire time you are using it. But it is not as good as a proper hardware wallet or dedicated airgapped computer.