In your opinion, sure.
The whole point of passwords is that they are keys for locks on your systems. Can you guarantee that your LP-stored passwords are safe, 100%, that no one has access to them?
I can guarantee no one has access to mine. 100%. My drive is only connected when I need to use it to log into something and then disconnected.
It's silly to think you can fully entrust all of your passwords to an online company and have them 100% secure. And if you think that is immature, that's your right. As it is my right to think that this is a silly thing to do.
I just went through my last pass accounts and I had 250+ passwords saved in there. I managed to get rid of about 75 of them, for things I don't use anymore.
I cannot guarantee that my accounts will always be 100% safe. But I also do almost everything online, I work from various computers at home as well as computers from work. i access my various sites and such from my mobile devices, cell phones, etc. For example, I like to look at elevenforums.com from home, from work, from my phone while traveling, etc. for me, it's totally impractical to save the passwords to an external drive and then have to carry the drive with me 24x7 so that I can access from all of my devices. For somebody else, none of this may be applicable and another solution is the best option.
What I have done to stay as safe as possible is that I have a small collection of accounts that are far more sensitive than anything else. These are all together in 1 folder in LastPass. About once per quarter, I can go out and change the passwords for all of these accounts (less than 20 of them), and also change my lastpass master password. Each site has a unique password.
For everything else, like elevenforums, tenforums, sevenforums, Netflix, etc.....if these sites get popped from a security breach and a hacker bruteforcing my password gains access, I might lose access to the site or get a post that I didn't make posted to the forums. I'll then have to somehow figure out a way to get back in. None of these are really mission critical apps, I'll survive.