Weird offer to get paid staying longer in AIRBNB Shinjuku

I have a airbnb booking in Japan next week and the host just send me and message if I could extend the booking with 2 nights so it becomes a month in total. He claims to get benefits and will reward us with 20.000yen and a free airport pick up. I must say, somehow this feels shady. Can anyone confirm either the host good or bad intentions?

This is the message:

Hello🥰

Your trip is coming up!😌I have a suggestion, so I'm reaching out🙇‍♂️

According to Japanese law, if I can sign a monthly contract with guests staying for 31 days or more, I can benefit from the government. Would you be willing to cooperate with🙇‍♂️ that procedure?🙇‍♂️ (Even if you change the number of nights from 29 to 31, there will be no change in the accommodation fee🙇‍♂️)

If you can help us with this procedure, we will refund you 20,000 yen and arrange a free pick-up taxi from the airport on the day of check-in and arrange a free pick-up and drop-off taxi from the airport on the check-in date.

If you can cooperate, we'll let you know the procedure later😌

Thank you🙇‍♂️

by momentumiseverything