Can I sign a 5,-deposit current account for personal travel in Japan?

Yes, in fact, the visa for free travel is not so strict.

Because you are not allowed to apply for free travel, you have to go through the travel agency, so the review is actually conducted by the travel agency. If the travel agency allows you to pass, the visa can basically come down, which is equivalent to the travel agency's guarantee that you are ok. However, if something goes wrong, the travel agency will bear the responsibility, so the travel agency audit will be stricter.

As you said, it's all about the travel agency.

My friend came here. One of them started his own company, and the requirements of the travel agency were very low. As long as he got the company certificate, he didn't need anything.

The other one worked in a big company, so he asked the company to issue an employment certificate, and then he mortgaged a lot of things.

So everything came from the trust of the travel agency. He didn't trust you, so he asked for much. He thought your materials were safe enough, so he asked for less.