this makes altcoins with PoS have no underlying value in its coin creation. thus reliant on value from the features of what that coin can do/be used for after the creation to keep the coin active/alive.
I disagree with that first statement, since there's essentially the same "intrinsic value" for both PoW and PoS coins, which is what you wrote in your second statement, i.e., they're worth whatever people are willing to pay for them based on various factors. I don't buy that whole "bitcoin is backed up by all the work and electricity involved in their creation" argument. I never did, because it makes no sense to me.
The good thing about PoS coins is that you can earn income from them, which isn't the case with bitcoin. And a few of them are useful for their smart contract functionality and so forth. The main problem I see with them in terms of their utility as currency is that people are incentivized to hold them and not spend them--and that also isn't true for bitcoin.
You have to admit, PoW coins do use up a lot of electricity, even if it's a small amount compared to other things. I happen to like the idea of being able to mint new coins simply by running a wallet, but I'm also aware that that particular feature can lead to centralization of the coin if the majority of them are in the hands of whales.