if u have bootmii @ boot2, u should still be able to recover from bricks by accessing it when u need to by holding the sd card in place only when the wii boots up. Once u see the bootmii menu, u don't need the sd card in the wii anymore, u can just launch the HBC and recover from w/e problem u have.
And if u don't have bootmii @ boot2, using priiloader u will still be able to launch the hbc in the event of a brick, as long as the brick doesn't involve uninstalling or stubbing your system menu IOS or System Menu
Lets put it this way, as long as u don't f*ck around practically trying to brick yourself, u shouldn't need to ever perform a nand restore. But u should still keep your nand backup, it can still be useful in the event of full bricks and infectus nand restorations.
The only thing u miss out on is mymenuify, but if u have priiloader or bootmii @ boot2, i would say it is safe to try installing a theme while holding the sd card in place (install process only takes 3 seconds-ish), and u will be able to recover even if shit gets fucked up.