I haven't installed bootmii, have I made a mistake?

So I installed the HBC last using letterbomb and I skipped the bootmii. I was playing around with emulators and stuff last night and a couple of times it crashed and left me a little worried in case I brick the machine

My questions are, do I need bootmii?
Can I install bootmii WITHOUT having to reinstalling HBC?
How the hell do you back up stuff with it?

Sorry if I sound stupid, I've looked around the web but I'm still confused?

You don't need BootMii but it can be helpful to have a backup of your Wii's memory. For most homebrew apps it is harmless if they crash. Emulators won't brick your Wii. If you'd like, you can still install BootMii without doing anything to your existing Homebrew channel. All you have to do is run the HackMii Installer again, either from an exploit or from the homebrew channel.

Thanks for replying! Good to know the hardware shouldn't get damaged, and its cheap to replace I guess I paid £20 for my Wii from a pawn shop.

If I run the letter bomb again, will I lose the ROMs and stuff I already have saved?

No, Letterbomb won't remove anything.

I ended up reinstalling HBC and installing bootmii as an ISO. Don't think I'll use it much, but its there anyway.