I give Bitcoin and LN a continuous pass on UX for now. We're in the infrastructure phase -- growing trust and improving reliability matters far more than UX. Before you know it, there will be 20 years of development and battle-testing behind the tech. The UX can come at any point in the future, while a breach of trust would be fatal. It's a question of ruthless prioritization. Thankfully, the open source devs behind these projects are long-term thinkers, not ponzi-scheme enablers.
Lastly, the UX need not come from Bitcoin/LN. They are a protocol, not a product.
Are you based in the US? Because almost everywhere else in the world when you say checkbook, people picture movies from the 1970s.
When paying a home improvement contractor, they send me an invoice where they have an IBAN. I point my banks app at it, it pops up a screen where I just type in the amount that I wish to pay (and sometimes it fills that in automatically too), and within 5 minutes the contractor has the money on their account. Neither I nor the contractor pay any fees for this transaction.
Checking my chequebook, I see it's well over a year since I last used it.
I've written less than 50 in my life, mostly for mail-order stuff back 15 years. In the past 15 years I've never even owned a cheque-book, the banks just don't give them out.
Also quick question: When was the last time you thought about the swipe-fees for your CC? I'll answer for you: Never. Yet with BTC and other crypto's this is a concern. And please, don't even talk about "Oh it's gotten better with the lightning network" or "The new QRS spec will speed this up", it's really just embarrassing.