Hi @juanmolina, great questions! For "sub-name" creations, there is no need to pay additional USD5 for them. For example, if I already purchased juanmolina.eth, I do not need to pay another USD5 to create awesome.juanmolina.eth. However, I do need to waste some ETH GAS to create the record by interacting with the smart contracts.

Hence, what I did was that I have purchased a number of Steem related names for potential users to choose from to create the sub-names. For instance, I am now the owner of steemnetwork.eth and steemleo.eth. I therefore do not need to pay additional USD5 to create culgin.steemnetwork.eth or culgin.steemleo.eth. I just need to pay some GAS.

So, I should be able to cover the costs through curation rewards by receiving delegations from Steemians. At this point I just hope to cover costs and bring the concept of ENS to Steemians so that we can all benefit from its convenience.

Regarding your next question. It is true that some privacy advocates advise to use different ETH addresses each time for your transaction. The idea is that you do not want a public address to be easily traceable to your identity. However, for people like us who are building a following on social media, we have kind of "given up" our need to remain truly anonymous. For instance, you cannot be changing your Steem username all the time for each transaction, can you? :)

The recommendation is to tag an ETH address that you don't mind being linked to you to the ENS name. This should generally be used to receive donations or for publicity. For other sensitive transactions, you should still want to use other ETH addresses that are not linked to your public image.

I hope that clear some of your doubts and I noticed that you have joined my Discord server, so we can always discuss more over there :)