I love mine. It saves hours of work.
Stoicism. The two major figures that I use to discuss stoicism are Viktor Frankl and Epictetus. Epictetus was born a slave and was crippled by his owner, but eventually was freed and found a happy life teaching Stoicism. Viktor Frankl wrote about finding meaning in life even living in the concentration camps. While not explicitly Stoic, his Logotherapy lines up very well with Stoic principles.
As for the spiritual component: https://stoickai.com/2019/09/19/the-stoic-god-a-call-to-science-or-faith/
There were no locks of the booths, and phones were in fact occasionally stolen. But it was generally not worth the hassle, and so there were no locks. Plus they were meant to be accessible 24/7.
Finally, many times the phones weren't in the booth and we're just mounted to a wall. The booth was to give you some theoretical privacy and reduce background noise, that's about it.
I'm not as stubborn as I seem, said my knuckles to the concrete