Checking the payee node id in the send dialog is always troublesome, the long hex value can be as confusing as typing a bitcoin address yourself. Just like every other thing in Bitcoin, a visual representation of the payee node id might be helpful.
There were suggestions on the Lightning dev mailing list that called lighting user-facing wallets to add an icon identifier for the id so that we can check if its the correct one, after all we as humans are much better at remembering visual cues that random long hex values, there were counter proposals that suggested using Chernoff Faces, as humans are best fit in recognizing small changes in faces and another that suggested using strings of seperate words, like BIP 39 seeds, that are easier to recognize, or memorize, than random hex values.
payment_preimageis a suggestion by developer Jose Femenias, it is used to enable sharing a common secret seed between an offline device and an online LN node, both the devices calculate the same
per_transaction_secret, the node encrypts the PIN within the
payment_preimageand then when the LN wallet receives the
payment_preimageit decrypts it showing the PIN, this is provided as proof of payment to the offline device.