I had a somewhat unpleasant experience just now with the binary vomit flood in full effect at the moment, doing a submarine swap using Phoenix wallet.
First problem was the fee it set was like 1/8th of the average fee for the next block.
Second problem was the transaction has no RBF, and I was unable to push it forward and it may be stuck for a day or more.
Just a heads up in case you are using it with on-chain transactions, I advise not to, find another wallet that actually has RBF for on chain. It is the swap service that has to send out the tx, I guess that's the story with that.
The lack of option to set the fee manually in the on chain payment interface of Phoenix is a really annoying thing for me today. Sats jammed up in the wires, no way I can see to fix it. They aren't my keys, it's a submarine swap.
Still super excited about LN but I would enjoy taking a certain set of black sunglasses and crushing it in a hydraulic press so hard it is vaporised.
I still say that no cap on witness data per tx is a dumb idea.