Except IRL you always have full deflection available after trimming because trimming simply displaces the stick, Which is not what is happening in the sim unless you have an FFB stick.
Since this is a wishlist thread I don't understand why we have to argue about something when you don't seem to get the point in the first place.
It's an option for the F-5 that some clever dev decided could be a good idea, and I simply wish that it would be made an option for all A/C that requires manual trim.
If you have the F-5 and fly with an ordinary spring centered stick I encourage you to try it out, so that you know what this is about. Otherwise this conversation is kind of pointless, sorry to say.
And to repeat myself: You can try to jump in the MiG-29 or SU-27, trim full forward, pull up control overlay and watch what happens to your input when you pull the stick back. It will never reach the bottom of the Y-axis.
Here is a different thread in the F-14 section for the very same option. It's worth a read.
https://forums.eagle.ru/showthread.php?t=258198