Vaccine passport

Just wondering if anyone has obtained a Vaccine Passport from their local municipality yet?
I've had my 2 jabs , and was at my local city hall recently and applied for a Vaccine Passport... I was there doing other paperwork unrelated to the Vaccine Passport, but seeing as I was already there doing other paperwork, I figured I might as well get a Vaccine Passport while I was there...
From what I had read in the newspapers, I had to present proof of vaccination, passport, identification, etc., which I did...
However, I was told that I needed to to proof of the dates I was departing Japan as well.
My question is - Has anyone obtained a Vaccine Passport from their local Town Hall, and did you have to provide proof of intent to depart, ie. an airline ticket, airline booking, etc.
Is this rule particular to my municipality perhaps?

proof of the dates I was departing Japan as well
That sounds odd. It is not like you need to be travelling to apply for a regular passport. But, a quick search suggests it is correct, at least at the moment. On the Yokohama page about vaccine certificates it states "Accordingly, the following persons are not eligible. • Persons not using the certificate for travel overseas"
https://www.city.yokohama.lg.jp/lang/covid-19-en/vaccine_certificates....
I will apply for a "vaccine passport" as it will probably be useful next year, but I was going to apply online.
Note, the following article is quite useful. It does say "Because priority is given to those with immediate travel plans, the online application will require you to disclose the country you are travelling to and your anticipated travel date. " so that is probably why they asked for travel dates - you could have made some up as "anticipated" as opposed to "booked".
https://www.timeout.com/tokyo/news/japans-vaccine-passport-what-it-is-...

I checked my municipality’s website, and they do indeed state that only those who have travel plans are eligible at the moment. They have a list of countries that require such a vaccination certificate, so if your travel plans do not include any of those countries mentioned, they might question you. I was thinking of applying for one soon too, but if I am going to do it I’d have to make up a plan too.
By the way, in my municipality, it is either in person or by post (no online application).

A little bit more hunting on my local city website (立川) also states only for those planning for travel and no online application at the moment. I also noted that the certificate includes the passport number, so needs to be re-issued when my passport changes (fortunately, not for a while). I also noted I'm in the 4.4% in the 12-64 age bracket that have received a second shot, but the numbers getting vaccinated are encouraging with a lot of people being processed and the site I used very busy both times with several hundred per hour receiving doses. (For the 65+ group, over 75% locally fully vaccinated.)
The internet also randomly pulled pulled up the page for the neighboring Hachioji - similar restrictions.
I suspect because it is a new process the various places doing the processing do not have much capacity yet - hence the 7-10 day timeframe to issue the certificate.

Thanks everyone...

the standing point of Japanese government is that they don't want to issue that kind of the certificate, because it may lead to the discrimination.
but, they also don't want that residents have unnecessary inconveniences in foreign countries. so, they want to issue the certificate only in the case when it is necessary.
by reading of the post, I think it is not clear that OP necessities the certificate or not. if he/she wants to get as one of collections, he/she should not do that.

also, although the government does not prohibit emigration and immigration, they expect that residents don't go back and forth with un-necessity. it is not a good time to do that, as everybody knows