Use golden apples for story?

I recommend to save your apples on events especially on lottery events. Story quest are always available for you to finish.

I did use my apples. I used around 4-6 apples to finish Camelot, because damn the story is fcking good I can't wait 12hrs for every two section. So yeah, I beat all of Camelot within 3 days.

If you ask me whether its necessary, ABSOLUTELY NOT. I do it just for fun and just because I like it. If I am a robot with no will , heart, and of course always being objective... What i just did was dumb. I agree that we better save it for event. Did i regret my decision? Absolutely no. I am satisfied that I finish Camelot way faster than most of my friends and fellow players, and the story is totally worth

Generally it's better to save them for events but this game gives you lots of apples so long as you don't insist on clearing all the event shops so I'd say it doesn't really matter either way.