Basically just use them for the monthly quests (play 50 µ's/Aqours/Nijigaku/Liella songs) and maybe daily quests if you are lazy. Excluding the two monthly event groups (which you'll most likely play manually most of the time), you'll be spending 100 tickets each month for the other two groups. The game give you way more than that so this looks like my best use for them (I still have over 550 skip tickets right now after finishing all the monthly quests). Enjoy saving your time for better QoL.