you already answered your own question:
1) as long as you have that media which works fine, no reason to upgrade
2) atm upgrading G7P9 would also mean to crossflash to Retail firmware B7x9 (x=T is latest while S appears problematic) which in many peopleÂ´s opinion will void your warranty (opinion! no one knows for sure).
So as long as it is not necessary, you dont have to do it. P9 appears to be a quite fine firmware so far, and even many Retail owners are staying with P9 so far if you look around here in the board. I am using G7P9 as well as I dont want to crossflash (so far).
Have fun writing and all the best.