People still don't know if legacy, segwit and native segwit addresses are compatible with each other.
They are, but silly outdated exchange software is not updated with Segwit BECH32 address recognizer even in 2023, which causes sending to these addresses fail. Otherwise native segwit would have been the golden standard a long time ago.
Personally I do not implement P2WPKH-P2SH ("3") address support at all, just native segwit, and legacy addresses for people stuck using outdated software. Taproot support is also questionable and it's only really useful if you are making scripts. Otherwise it is not much different from native segwit. Of course, support for
sending to all of those addresses are important (and only involves implementing Base58 and Bech32 decoding - which would already be present if you are supporting legacy + native segwit), it's just the wallet generation part where you can safely stick with legacy and native segwit, like Electrum.
Not many people aware of lightning network and how to open a channel.
Also valid, though in my OP I was referring to Layer 1.
Not many people know what is CPFP, RBF and sat/byte.
Arguably they shouldn't have to, that is the job of the wallet software to handle. All users need to know, are fee priorities "High" "Medium" and "Low", which the software automatically chooses the appropriate sat/byte value depending on network conditions, and "Refund" which is just a double spend using RBF (which is on the brink of being enabled globally for the entire network anyway).
Is it so difficult for crypto developers to create a UI or anything that would make crypto easier/ more accessible to people.
The internet was "difficult" once...but now even grandma can surf the net. When crypto will be easy enough gor grandpa and grandma, mass adoption is in.
There is a part of reason in this. If Bitcoin were to one day be used with the same adoption that the internet and cell phones are used today, there should be very user friendly applications, but I don't think it will ever be used with that level of adoption because of how valuable it is. Most likely it will be CBDCs or some shitcoins that everyone will use on their mobile, while Bitcoin will tend to be treasured more as something valuable. Even with highly developed LN or other solutions it doesn't make much sense to spend Bitcoin and store dollars or CBDCs, rather the trend will be the opposite.
I disagree about shitcoins, I don't see anyone using something like $PEPE as cash material. Or even DOGE which has not received an update to its full node for
an entire year.
CDBCs are more concerning, but then again it will probably just be implemented as another way for your banks, Paypal and co. to store your money. In other words, people don't actually have to learn how to use the CDBC because their financial apps stay the same, it's just the banks being forced to adapt to that. That's how I believe people will eventually be made to use CDBCs.