You should always be provided a hide if possible to give them a safe retreat to go to should they feel threatened or want to escape the light, remember despite you wanting to see them constantly think about the best interest of the specimen. That's always #1
If you take out the hides and force your tarantulas to be out in the open all the time they will be stressed out. If they are too stressed they will not be as healthy. They will also be a lot more likely to try to bolt out of the cage or bite/flick hairs when you open the cage to feed them or clean the cage because they don't have a safe place to retreat to and will feel trapped and threatened.
To be honest I can't imagine a Theraphosidae living without an hide (I suggest always a piece of cork bark if possible, better than those plastic kind of caves) and a water dish.
Even to obligate burrowers, always a nice piece of cork bark, that substrate alone because "they burrow at the end" mentality is IMO horrible.
However my experience with the Theraphosidae you mentioned slightly differs from yours. I have (and had prior of course) the T's you mentioned, including A.geniculata, and by far I can say that G.pulchripes, B.vagans, and A.geniculata (probably IMO the best 'display' Theraphosidae ever) are for the 80% always out in the open. Aren't 'Haplos' eh...
bottom line is that every living thing needs to feel safe and secure. For Tarantulas, that means a way to hide if they choose. So yes, the hide is mandatory. You have chosen to be responsible for another living creature. Part of that responsibility is to provide for ALL of it's needs, not just the ones that are convenient to you.