I have seen people do that as well. Personally, I just foam the pots in and then I use bamboo BBQ skewers to punch holes it the foam. But I only do that so I can adjust the drainage of each planter. It's a very time consuming practice, but I think worth it so I can have plants with different needs all over the tank. Remember though, I normally have my planting figured out before I even start building, so I already know which plants need excellent drainage and which ones can have a soggy soil, ect.

I would suggest you utilize the coffee stirrer method since it's your first build.