Sure because we want realism in a friggin HTML Porn Game, right that's what we want.
The Game is good, the Gifs are good too but really... realism?!
NOTE: I write "We" because I think I'm not the only one that thinks so but I'm open to be corrected if the majority wants more realism in a porn game
Of course. You can work a job to get money. I didn't need to do that. I could just have a button that says "get money". You go around a town where you encounter different things, I didn't need to do that either. I could have instead just made a list of events that aren't connected in any way.
A game isn't a life simulator, but if you can extend your disbelief in the game world, you're more engaged in what's happening. At least that's how that particular theory of game design goes.
There is a bunch of "useless" flavouring in the game that doesn't add much in itself, and if looked at in isolation seems pointless, but I think it holisticly becomes a better game world the more attention you pay to the details.
A secondary point to having upkeep is to add another check on the player economy, which can get very powerful later in the game. Money inevitably stops mattering in the late game with the runaway effect of slave ownership multiplying your income, but hopefully this point occurs later in the game now for most players.
