It is not the same thing. I do not need to reason at all right now, I just look at the clock that shows times in relevant timezones. I know all the information instantly, without any calculations in head at all.
In the latter case, you do need to do math, because what you are getting is meaningless number and then you need to convert it to some kind of "how long after typical start of day" format to get information you actually want.
Ah, so you're saying you have a clock showing German time, and it did the "math" for you.
Imagine multiple world clocks, in the typical Hollywood command bunker look. Instead of each clock having hour hands pointing in different directions, they'd all have the same hour hand position, but different highlighted zones for waking hours (or "shift 1", "shift 2", "shift 3", for 24h duty).
In the latter case, you do need to do math, because what you are getting is meaningless number and then you need to convert it to some kind of "how long after typical start of day" format to get information you actually want.