That's very interesting & I don't think it reflects badly on their intelligence- only that they evolved with different life skills to survive. They're very tiny compared to things that would eat them, so sitting on the ground is asking for trouble, but they climb very well, plus they blend in on tree bark very nicely- not to mention the attraction small lizards (a big part of their diet) have to run up & bask on trees. I've only known one spotted python (that I still have) & she prefers being above ground most of the time too.
That's very cool that you found this study- as it has implications for your little Antaresia too.