I agree with you, some field notes are a pain to get, I spent 3, 4 days now and
- some fates appear once or twice in one/two hours, if you don't manage to get there in time, it's dead.
- if there is a lot of people, they beat the fate in 10 seconds and if you don't have time to hit something, it's dead.
- low chance to participate in duel (+ you get a lottery to be choosen for this duel), if not, you have to wait again and repeat.
I saw people who did 50 times the same fate for one note, it's just ridiculus.

If we could buy the notes with the coins, it would be great.

I wish more people comment here so it can be seen from the dev team