Whenever you're confused about a vague term, just think - does my usage cost the service provider more than they earn from me? That will be your answer.

It's not really about the specifics of what the bytes represent, it's whether the transportation and processing of those bytes makes Cloudflare money. Either now, or a likelyhood of future earnings.

I'm not sure what you mean by "regardless of the final size", because the final size is going to be one of the most important factors.

A constant stream of small encrypted files doesn't sound like a plain old web page, though. (Unless they're extremely small bits of live data.)