Sub wiring diagrams

I've been doing some searching and came across some wiring configurations and noticed one that puts 2 4ohm subs into an 8ohm load, I was always told that 8ohm was not good that 4-2ohm is what you want. So why wire it into an 8ohm load?

LOL...8 ohm is not good??? hahaha...not good. Well if your stuck with two 4 ohm woofers and say you have a 2 channel amp that is not 2 ohm stable bridged than you have to either wire it stero or bridge the amp with the woofers wired in series for an 8 ohm load...same power ouput as stereo 4 ohm though...Just less wires and clutter I guess. There's nothing bad about an 8 ohm speaker...It's just a higher impedance.