I like setting containers on top of something absorbent, like a bit of toweling or cotton flannel (or denim, or Tee shirt material, or a white sock ...)
If the absorbent pad isn't damp, neither is the bottom layer of soil.
Or the hole got plugged!
When I overwater or it rains, the pad will help to pull excess water rapidly out of the bottom inch or so of soil. Otherwise, water tends to "perch" in the bottom layers of fine or water-retaining mixes, so much that roots can't live in the bottom few inches (periodic drowning and rotting). And it just can't be healthy to have waterlogged, anaerobic soil anywhere in a pot.
My guess is that many potted plants avoid this fate by having root balls so thick that they can drink up the excess water so fast that they drink the perched water before they can rot.
Like a frat boy with his head held in a punch bowl: he's fine as long as he can drink the whole bowl before he drowns.
I like that saying: "The three most important thing to potted plants are drainage, drainage and drainage!"
