I don't think those enclosures are that good for tarantulas. Fossorials won't get the correct amount of substrate because the doors start to low to the ground. Terrestrials need more substrate height to make it safe from falls. And as you said the airflow can get greatly reduced.Airflow can be greatly reduced by filling the enclosure with too much substrate, effectively negating the design
I currently use them with my frog (works great!), one leopard gecko (same) and a colony of grass lizards in two enclosures( one will not hold humidity worth a damn and the other needs a fan to get rid of excess humidity).