The fact that you can get max 10 seal scrolls per month, excluding February, it's a good source of getting seal scrolls. After spending on scrolls I using prep for the upcoming certain rebates. So for this week and the upcoming week, I've been using my points on threads for the battle armor rebate. After the rebate is done, I prep for refinement rebate. Once the refinement rebate comes and goes, I go back to threads and I repeat the cycle.

In the monthly event, you can earn points by doing tasks such as doing arena, battling your friend, doing ranked battle, pulling summon scrolls, etc. These tasks are separated into 4 weeks and each week lasts only 7 days. This means you can only gain points from tasks up to the 28th. You use these points to get items like you said already seal scrolls, refinement runes, clothing threads, a ninja frag, summon scrolls, and purification runes. After the 28th day, the redeem counter resets so you are able to use the points you farmed from the 4th week. For example, in the 4th week, you can save 600 points to use to get 2 seal scrolls in the 4th week and after the 28th day.

I already said I spend my points on seal scrolls but I can do both seal scrolls and threads or runes depending on the week I'm preparing for the rebate. So for each week I try to get 300 as fast as I can since I can only redeem seal scrolls that cost 150. Then the leftover points I can earn goes to either the threads or runes. Once the week is over, I go after seal scrolls and I repeat the process. It's your choice if you want to go after only threads and refinement but you probably have leftover points and might miss out on the max 10 seals you can get.