In this case, "-ux" isn't meant to refer to these dmesg(1) options
-u, --userspace
Print userspace messages.
-x, --decode
Decode facility and level (priority) numbers to human-readable
prefixes.
but rather to a recent User eXperience
epiphany I had using dmesg.
Most of the time using dmesg, my concerns are immediate: I'm looking to
see errors that occurred very recently. As such, I'm not so interested in
the exact and absolute time they occurred. So, the default timestamp used in
Linux, of the time being denoted in seconds-since-boot, has been a good
enough representation.
When I wanted log information about events that happened over a longer time scale, or in cases where the time by the wall clock mattered more, other logs with those kinds of timestamps usually served well enough.
About a month ago, though, there was an event I need to which I needed to
look back at that had happened several days before. I also needed to
coordinate information from dmesg more exactly with events elsewhere.
Converting that timestamp into a wall clock format became useful enough to
me for the first time that I wanted to figure out how to do it. I did a
little digging and found the -T option.
Like a kid with a new toy I've been enjoying using it routinely with dmesg.
It' a small thing, but fun.