Disclaimer: I'm very new to Bitcoin so have patience.

I made my first transaction this morning to a wallet. It cost me a measly $4 for about an $850 transaction. That's not all that much but it still got me wondering why. At that point, a debit card is still way better because i paid a $0 fee on a sausage egg and cheese mcmuffin shortly after. This is a big problem for Bitcoin I'd imagine. Imagine a currency we want use and have the general public adopt. But we tell them it will cost them $ every time they use it. It's simply not going to happen.

From what I read, the fee goes to the miner who mined the block of which my transaction was contained in (correct me if I'm wrong). But why? Am i simply paying for the electricity it takes for the miner to verify my one transaction? or is it something else? what exactly is being paid for? the default 1000 satoshis/kB seems pretty arbitrary. How is this number even determined in the first place?

It would make sense to me for the miner to eat the cost of transaction verification as a cost of doing business. Clearly its very profitable mining for the huge mining pools. So by eating the cost of the transactions, would it still be? i don't really know because i don't know what it's actually paying for. Bottom line is fee to consumer to simply make a transaction is a non starter for any sort of widespread adoption. Keep in mind my knowlege level is very low, so I'm really just trying to understand where this money is going and what it's going towards and most importantly how you can make the currently better and more approachable than just cash or a credit card that don't charge fees