Well let's just say that it's very useful tool to anyone else who didn't like to read the lines in the VN for the second time, although sometimes it does its job too well because the button would obviously skip everything that already read, regardless if the reader want to re-read the lines or not. Still, the usefulness outweigh it's potential drawback anyway, seeing that it would help someone who stuck in reaching the route that the player want, moreso if said VN has too many inconsequential choices which is prevalent in the older VNs. Said potential drawback is quite rare anyway, in which it only happen in the old Chaos Head where the text keep skipping if the player need to trigger the delusion at the certain instances in order to get the bad ending, and you can only get the bad ending in the second playthrough which mean you already read the lines.
For skip the scene, the closest one that we have is skip to the next choice which skip a lot of scenes anyway if the developer didn't make much choices in the first place outside of the sex scenes, and one of the VN that apply that is prominently Yuzusoft VNs. As for the VN that explicitly mention skipping the scenes, well maybe only Fate/Stay Night that still apply it until now. Anyway, this feature is obviously very useful if you want to check the Japanese guide before making the English guide, or maybe checking the gallery seeing it only unlocked after you finished the game. Granted you can also do so with the regular skip, although it's obviously faster if you can skip the scenes.
No much to say that the auto mode is mostly useful if you record the VN to make the playthrough to upload it on Youtube, although it won't be useful if you prefer to rush the game seeing auto mode speed is usually too slow if you're fast reader.
That's all for what I can write in regard of this topic.