Question about G49

This may be a purely academic question, but nonetheless:

G49 seems to be 'modal' whenever a G43 Hn is not in effect (also, the 'n' tool must have a non-zero offset in order to 'turn off' G49 and 'turn on' G43 in the 'active g-codes display').

I say the previous because whether or not I specify G49 in the RS274NGC_STARTUP_CODE , my machine shows G49 under 'active g-codes' after every restart. (I'm using QtDragon, and this is right under the last axis in the DRO).

I guess my questions are:
Is there any reason the G49 needs to be specified in RS274NGC_STARTUP_CODE ?
It appears that tool offsets are not persistent across re-starts: but is there any case outside of custom programming that would make them persistent across re-starts? (I guess this might be an answer to my first question.)

Thanks!