To each their own in my opinion. I would never recommend someone to feed outside of the snakes enclosure simply based on nature and their proclivity towards being skiddish. Taking them out of their hide and exposing them in an open tub just doesn't seem "natural" to me. However if it works for you then keep it up. I have a large sample size with my collection and the cage aggression myth is just that from my perspective. There are snakes that have attitudes and snakes that are calm as can be but that has little to do with where they are fed but more so about personality difference. More important than where you feed them is that they are eating consistently so if you have that battle won then.