Cross trimming was created so a pilot could do just that;
Trim the elevator without taking ones fingers off the elev stick.( a good thing) or negating having to reach over with the left hand.(another good thing)
In the older days of analog trimers adjusting the trims happened right now...(Another good thing)...
You as the pilot did not have to wait for the beep ...beep... beep and delayed action or over shoot
of digital trims...(a bad thing, espeically if you have a bronking buck on your hands)

Standardization of whatever your radio setup is will result
in fewer crashes due to brain farts associated with switching transmitter setups, styles,switch positions...

Would love to see new digital radios come with quick
analog style trimers. prefer a radio with analog trimmers for maiden test flights....

Crosstrimming is a good thing.....if you have been doing it....the changeover can be dangerous if your a creature of habit.
Could shut the turbine off easily if a B fart occurs or
you tell a helper...."give me full up elev trim" and he does.....shutting the engine down.
(avoid this scenario by making sure to tell the helper ahead of time).

How often have you have to retrim for takeoff/landing or so on is another consideration.

You can always go back....