I prefer wetting the tunnels a little than just over flowing the water dish as that is something I keep in mind. Granted I'm not dumping water down there but a little water trickling in does not seem to hurt anything.
You posed your question in a way that doesn't have a definite yes or no answer. The answer is that it depends on where "species x" comes from and what adaptations it has evolved to combat desiccation. Providing drinking water will allow a spider to hydrate itself, providing a humid microclimate in captivity by way of moist substrate prevents the water from leaving the spider's body for those species that exhibit signs of a more permeable exoskeleton.
This is a very good post. I can further attest to the main idea here by sharing my observations of Aphonopelma hentzi in my city. During the hot, dry summers in Texas Aphonopelma hentzi will plug their burrows during the day and open them at night. If it is especially hot and dry, the majority of the population I study do not even unplug the burrows at night. I imagine the spiders reduce their metabolisms to prevent the need for food and water while sitting in those closed burrows.
People and their lists... What you are asking for will provide the same information as the recommended humidity levels in a care sheet that so many abhor. The keeper who hasn't had a lot of experience with a lot of different species of tarantula will usually fail to realize that most species can tolerate a wide variety of humidity/ moisture levels. I understand the emphasis is more on providing the best care for one's pets but because tarantulas are cryptic in their behavior, and they certainly can't tell you verbally, there needs to be some desire for experimentation to find answers. Go ahead an pour a cup of water in the Chromatopelma cyanopubescens or Pternochilus murinus enclosure and see what happens.
Looking at your join date -- you already have the list I want -- in your head!
I would never let a haploma enclosure dry out completely...damp sub for them is the way to go....same for most Asian t's.
Why would anyone keep an Asian terrestrial dry? Chris Allen, the big Asian collector/breeder in the US keeps all of his on moist substrate. Asians can easily dehydrate.
I'm gonna pick up on that and say that I'm baffled everytime that I read people keeping A. geniculata bonedry. Sure, you can do that. Should you? No, not by a long-shot. Their habitat is close to a damn and quite moist all year hence and like most T's, they will adapt to some point but that doesn't mean they "feel comfy". And by experience with E. murinus I've witnessed a female that was kept bone-dry behave extremely "unnatural" compared to other females. So, yes, it can influence behavior, feeding response, even generally if they're easily bothered or couldn't care less.
Funny thing is I thought that too, yet our A Genic seems to despise most substrate, refuses to come out and when she does she's on the walls. When it's dry she's out on full display.
There's other factors it that too, like temp, humidity, and air movement, both in the cage and in the room.
I didn't say I keep her on completely moist substrate. Half her substrate gets wetted down some, the other half stays dry. That way, the T can chose were to sit and she seemingly likes it that way. Once it's dried out, I repeat the process - all that in addition to an overly sized waterdish that provides additional humidity.
That's exactly how i keep my Acanthoscurria geniculata all the year.
But you see, where i live is more on the "hot and humid" than warm and dry, so i think the water dish is enough. Maybe i'm wrong, but.
Like I said, there's other factors indoors, like temps, humidity, air movement. Those are impacted by how much you run your fans, furnace, and/or a/c.