Not the only slogan actually, "The Dot In Dot Com" ran with several important campaigns at the beginning of the nineties and was a crucial security public service announcement that's explained here :
The trailing dot then means the name is to be used actually exactly only like that, it is specified in full, while the name without a trailing dot can be tried with a domain name appended to it. Or even a list of domain names, until one resolves. This makes people want to use a trailing dot at times, to avoid that domain test."
It's not the software licensing, but the independent consulting entourage that's the problem : internal confidential big four accountancy information told to me without any applicable restrictions on my repeating this put the cost of each Oracle database instance deployed in the F500 at over one hundred million dollars, due to the third party make work.
I'm much more in in why nobody is apparently interested in the history of anti competitive business practices including product dumping and downstream supply chain hostage taking, that this article almost implies have been accepted eccentricities of Clark for reasons unspecified but implied to have something of a cult worship element involved.
there will always be edge cases that you don't catch until they show up live in in prod.."
in reply to,
"How do you measure robustness except with failures / years of service x times deployed ?"
The only viable live testing environment that springs to mind might be running your test code synchronously at the atomic level with production, which I'm convinced only IBM Z/OS on a Parallel Sysplex cluster running CICS can do.
https://daniel.haxx.se/blog/2022/05/12/a-tale-of-a-trailing-...
THE money quote :
The trailing dot then means the name is to be used actually exactly only like that, it is specified in full, while the name without a trailing dot can be tried with a domain name appended to it. Or even a list of domain names, until one resolves. This makes people want to use a trailing dot at times, to avoid that domain test."