They don't, I was dicking around with them in creative.
Who do you think greg is, Soaryn?
Hah, well then, they're still some fairly nice looking blue walls. They'll go in my blue room. Yes, I have a room for just blue. Or I will, when I build one!
1B EU goes faster than you think. Matter fab is very hungry and will allow me to bruteforce iridium for ALL the toys.
As I said in my post, matter fabricators do not apply as they are an end point for energy, or an "energy sink". You can put up to 8196eu/t into a single matter fabricator (and after that, you build another). That means that you need to produce that much energy otherwise your 1,000,000,000eu storage is going to run dry, unless, for some strange reason, you turn off your matter fabricator.
Energy storage with EU is designed to work like a capacitor as well as a battery. Your systems generator power at a specific rate, but your power usage is not specific usually, so you have a fallback for power when you need more power, and when you are using less power it builds up. A matter fabricator is a constant massive drain on your power, which makes any energy storage useless.
If you've got the resources, make a fusion reactor so you can run four matter fabricators off of it at the same time at full power usage. Then make a second fusion reactor to brute force iridium (or switch off on the first whenever you need more iridium).
If you disagree, tell me how, exactly, more energy storage is helpful to you. I'd love to know if I've missed something obvious.