Think about it like this. Bearded Dragons

come from a desert environment. Most will live their entire lives without ever seeing a pool of standing water

With that being the case WHY would they evolve to soak
hydration into their boby by setting in it. They wouldn't and they don't.
Indeed, habitat and evolution are often a good starting point to whether an animal has a certain feature or not.
However, in fact at least one desert reptile, the thorny devil, has evolved to do just so (they can stand in water and the water is sucked up to their mouth along the skin in little crevices). Likely as a by-process of being able to collect water that condenses as dew on his spine, where then also little crevices in his skin lead right to his mouth.
They get their
hydration from the food they eat. Their bodies are VERY efficient at extracting water from food. Their system actually does so twice during food processing. They can get like 98 to 100 percent of water that their food contains. That's partially why it's so hard to get beardies to drink.
With that, I absolutely agree

My dragon didn't drink for some months now (can't be sure if he didn't lick off water of plants, but I see him avoiding the plants after I have watered them). Poops look totally normal - just because the water in his food is enough. This also makes totally sense from an evolutionary point, and just by comparing to what our body does and what leads to water loss (mainly: sweating, urinating).
And indeed it's shocking for some people used to other pets seeing a bearded dragon normally isn't
drinking. I remember my mother-in-law asking me, when I told her Taco will be alone for 3 days and no worry, has enough food, "but with the water, what if his bowl tips over?" She (used to cats and dogs, poultry and small mammals), and I don't wonder, assumed Taco of course has a water bowl (he has not) and he will die or get seriously ill if he has maybe no access to water for 3 days in case said bowl would tip over.