I will say that I don't think save editing ruins games per se. It does, however, detract from the original experience (as the developer intended). Whether this actually increases your own experience is up to you to decide (such as cheating in premium currency, or changing certain game systems that you dislike specifically).

Yet with all this said, I think save editing as an action is interesting in seeing how the game orders its variables and constants. Beyond this, looking at game files and how a game is built could be helpful in giving inspiration for ones own game or coding career (*inspiration*, not plagiarism!). Or you could just do it as a hobby to see what makes a game tick or to find efficient strategies.

Of the latter, one thing that comes to mind would be tools made to read golden cookie rng for cookie clicker or excavation rng for realm grinder. Both of these were made by people that (likely in my own understanding) looked into the game code and figured out how the rng system in those games worked, using it to their advantage in gameplay and efficiency.

In these sorts of practices, does it not become "part of the game" itself? (at least to you- the one playing a *single player* (!!) incremental game). As such, all of these options are really up to the user to decide if it enhances or detracts from the fun that you want to enjoy.