I have data on the category rate of pulling kamihime at each rarity tier. For SSR, it's near 50%. It's not bad. Compare that to the 3% * 5 chance of pulling a SSR kamihime from an equivalent worth of SR+ kamihime tickets. It comes down to whether you want the SR kamihime or not. Keep in mind that SR+ kamihime tickets are in the Advent Battle event shop later on (1 per event), so you're going to accumulate them anyway.