Very expensive is a subjective term
I wouldn't call it subjective. I'd call it plain wrong. They could maybe be called a bit expensive when it was $150 for a hardware wallet, but not now.
A Ledger Nano S costs $60, but they often have deals on which take the price below $40. At the moment they have a pack of 3 for sale for $130, so if you get together with two friends, you can get one for $43.33.
You will pay $20-40 for a decent case to protect your mobile phone. You will pay the same for a nice leather fiat wallet, which offers no actual protection whatsoever. Why would you
not pay $40 for a hardware wallet which is incredibly more safe than storing your coins on a mobile app?
I didn't use Ledger before but what do you mean by saying you can manage more coins by using Electrum?
Some altcoins do not have support from the Ledger Live software yet, so have released their own wallets which are compatible with the Ledger Nano. Some of the useless bitcoin forks, for example, are not supported by Ledger Live, but have created their own forks of Electrum.
Also, I never heard of the reward you are talking about!
Some altcoins will reward you with a few cents if you buy and hold loads of their bags. This is by no means unique to hardware wallets.