LMAO @ the witty replies to this thread!
But, you guys are missing the point. Yeah, blow torches are fun, but lighting them and heating the pipe is time consuming. I like to streamline things so that I can get my planting done quickly. I have 30 earthboxes and I'm a lazy gardener.
The serrated pipe is much faster because I don't have to heat it up first.
You're not lazy. If you were, you'd just poke a hole through the cover with your fingernail and, if needed, enlarge it by tearing it, like I do. No tools= time saved by having to find them and bring them out.