I'm considering it for at least the snake (and I would def do it if I had birds). Even perfect husbandry can't prevent everything. Radiographs at my clinic are $210 for 2 views and $86 for each additional view, bacterial cultures can run $100-$375, etc.
I took my leopard gecko to a specialist in August and it was a $354 visit to run bloodwork since he had to be sedated to get a sample and then the cost to run said sample. It would have been nice to not have to put that on my credit card and have insurance cover most of it. Its easier for me personally to budget a few dollars a month rather than sudden large costs.
But it is at least now an option - you read it in posts all the time here "I don't have enough money to take my snake to a vet", the visit + diagnostics + medications only get more expensive with bigger animals. The vet costs for a ball python will be much less than for a 10 foot burm, simply because of the amount of medication needed to treat the same illness.