That depends on the pool whether you can use a btc adress as your user login

Looking at the pool, it says the following:

Code: (http://ckpool.org/#/)

Set your username to your btcaddress with any or even no worker extension, and any password.
eg: cgminer -o stratum+tcp://pool.ckpool.org:3333 -u 1PKN98VN2z5gwSGZvGKS2bj8aADZBkyhkZ.0 -p x

So, any adress you control the private keys over should do.

Quote

username "-u" is basically the entire receiving address in electrum wallet? And I can use any one of them since there are multiple ones?

yes.

One thing i forgot to note: the bech32 adresses (bc1xxxxxx), are *relatively* new. It could be that ckpool doesn't recognize them yet..?

In which case you should probably create a nested electrum segwit wallet.
You can still create these P2SH wallets using a quite unorthodox method described here -> https://bitcoinelectrum.com/creating-a-p2sh-segwit-wallet-with-electrum/

EDIT:
I do think they support native segwit by the looks of this post ->

Quote from: Artemis3 on July 05, 2019, 02:44:38 PM

Quote from: os2sam on July 04, 2019, 09:34:28 PM

Quote from: VentMine on July 04, 2019, 09:18:25 PM

Dumb question but does this pool support overt ASICBOOST?

Yep, dumb question.

This pool was the pioneer of overt ASIC Boost.

And native segwit addresses

So you shouldn't have to do all of the above.