Owning any animal requires being fully responsible for their care and expense within reason. Having said that, if my dog gets cancer I'm going to do what it takes to get her better. I would not, however, put my chameleon on the same level as my dog.
I'm also surprised that he's healthy. Seems like majority of posts are about some health issue, so I just assumed everyone's cham got sick on a regular basis.
For me it was how friendly this wild animal is. He's always comes down to his special spot and reaches out when he wants to climb up my arm, usually several times a day. While he's sometimes hesitant and slow, he's not afraid.
Regarding drinking water, I've had my chameleon for some time & I've never once seen him drink or lick water.
He does occasionally lick a dry branch, but that's just him marking his territory.