No one should be using on-chain Bitcoin transactions for in-person exchange. Partly due to the high fees, but mostly because of double-spending and lack of privacy. Lightning Network solves all of these problems. Fees are much lower, settlement is instant and clear to even unsophisticated users, and the recipient cannot see from where the funds originated.
Taxes are a different issue and that's up to each jurisdiction to solve via better legislation.
Don't you still have to pay the tx fee to open a lightning network channel? Anyway the whole thing lost me with the block size debate (always been a big blocker). Where are we at with lightning network adoption anyway?
Yes, an on-chain transaction is required to open a channel. But once open you can continue to use it forever, or until you (or your counter-party) decide to close it.
Lightning Network adoption is slow and steady. There are several newbie-friendly mobile wallet apps available [1][2][3]. Some nice improvements have been developed and pushed live in the last 18 months (e.g watchtowers [4] and atomic multi-path payments (AMP) [5]). There are now five Lightning Network node implementations (lnd, eclair, c-lightning, rust lightning, Electrum). And there are hardware projects working to bring LN into the physical space - one of which is my own project, a Lightning-only Bitcoin ATM named "Bleskomat" [6].