Impossible to destroy something that is designed to last literally forever.
You cannot destroy that which is indestructible.
This must be true for eternal hell to have any meaning...
IF
we were created as eternal beings, eternally self and other aware spirits and
IF we were all created with a free will and
IF there is an unforgivable sin, a sin that puts the person outside of all grace and
IF some of HIS creation chose by their free will to sin the unforgivable sin and
IF it is true that a little leaven / sin leavens / corrupts the whole lump / person / community, then
IF the only way to protect HIS Church and heavenly Family from these eternally evil people was to banish them from HIS heavenly reality,
THEN an eternal hell is an absolute necessity to keep the eternally evil ones from corrupting HIS heaven.