First of all, it is a monthly fee, but there is no problem even if it is several thousand yen. On the contrary, even advertisers who pay more than 10 million a month are fully effective.
There are no restrictions on the number of conversions or clicks required for optimization, and all accounts can be used in any situation. Therefore, it is not necessary for the user to make a judgment such as "Set to maximize clicks because the number of conversions is small" or "Because there is not enough data yet, let's make manual adjustments first". Even if you have only one click per day, or if you have one conversion per month, we will move toward maximizing conversions without any problems, so please try it first. I hope you can use it.
This is also a point peculiar to Shirofune, which is different from the data-dependent algorithm using simple statistics.