Morelia in general are more apt to be flighty than terrestrial species. It's they physical makeup. Carpets thankfully are semi sometimes if they feel like more stretched out and almost terrestrial which makes them easier to handle. A wild caught or farm raised carpet can be more defensive and not as easy to acclimate into captivity so if you want a good carpet get a multi generation captive bred from a proper breeder.
Carpets like all morelia are more of an intermediate to advanced snake so make sure you are ready for that type of snake if you want one.