To receive bitcoins, you must be connected to the Internet ????

[ormatr]

1. Oh yeah. This seed can be used to derive your private key. It is not the actual private key, but if you have access to the seed, then it is essentially the same thing.

As a user I have nothing to do with private key. its something generated at back end of wallet and wallet take care of it.

Fee is high because average number of transactions per day are gone up from 400k to 600k according to stats here https://bitinfocharts.com/comparison/bitcoin-transactions.html#3m