So mempool is only useful for fees. 🤔
Wonder how you could structure fees and have tx's submitted directly to a pool's node for GBT usage?
Discussion
It's only useful if you are mining with the node and want to collect fees from other txs. If you just want to mine your own txs you manually add them to the template.
You can also estimate fees for your txs without a mempool, but you can only do it against recently confirmed txs so it will be less accurate.
Every other feature will work the same except you deal with mined txs instead of not yet mined.