Is this a feature of the Lightning Network or just the Electrum client?

I don't think it's good for the LN in general if users are unable to start instantly receiving bitcoins.

I know this isn't the case for Layer 1 but think about it, imagine if you generated a wallet, but Bitcoin's design was totally different from how it is right now and you could not receive any bitcoins in a transaction before you made an outgoing transaction first.

It's a strange design choice, if you ask me.