[nmadden]

> The real thing exists largely because it makes proofs easier.

I would not say that. It exists because practical padding oracle attacks (which are adaptive CCA) have been known for decades. CCA2 very much captures real-world attacks. Is there any realistic attack that is captured by CCA1? (Or vCCA).

Padding oracle attacks also generalise to any kind of parsing after decryption. Padding tends to be studied because it is independent of any particular format/application and also part of several encryption scheme definitions. The definition of CCA2 captures very realistic scenarios - almost all applications do some parsing after decryption and so are quite likely to reveal an oracle. Would vCCA also capture such attacks?

[MzxgckZtNqX5i]

While it might not provide a direct answer to your question, this paper could be an interesting read: https://eprint.iacr.org/2021/1624.