Yes it is safe and ive been using it since i do engage and know about bitcoin.It is safe as long you didnt give any informations about your wallet and setting email verification and 2fa would really a good security into your wallet and now blockchain would really give you the access on your keys which is really nice feature as of now unlike in the past that they dont give they keys but now you can able to do such thing.
It's not as safe as a desktop wallet, and it's much less safe than cold storage. I've read about potential JS attacks that make blockchain.info vulnerable. The fact is, whether potentially devastating attacks are currently known yet or not, you don't control the software which controls your keys on blockchain.info. That should worry you. I'm certainly not sophisticated enough to understand the potential attacks, but I feel much more secure with my encrypted desktop wallet.
You can add 2FA to an electrum wallet too, if you want. BCI is better than a straight up 3rd party web wallet, but it's definitely not great for holding much value.
Yep, what you said is all truth. Web wallets are not really that much safe, though some of them can be highly secured, of course, but to a certain level. Their security is not guaranteed to be 100% safe (not sure if the most secured is even up to 80%). So if you want to save a large amount of bitcoin, I suggest you adopt cold storage for that. Use online wallet for a certain amount.