はい、全てご褒美です。

Yes, it's all a reward.

Refers to the verbal abuse from Cafe-chan at the end of this episode, consistent with the somewhat S/M relationship between Cafe-chan and the artist (exemplified in post #1865318) + readers. Not as evident here on DB, but it is a running gag particularly in the artist's live stream; see also Pixiv user tags in comment #1372003.