let's say that a modchip is the most reliable way to play backup game disks, but a twilight hack is still required to run homebrews, install homebrew channel and VC/wiiware channels. (for 3.3 wiis)
if you have a 3.2 wii, you can use trucha signed disks so you can install homebrew channel and run homebrew without the need of the twilight hack (and for this you need a mdchip)
if for you it's enaugh to run homebrews and VC/wiiware games, then you don't need a modchip, and can simply use the twilight hack to install the HBC and run homebrews from there.