The only reason I can think of is that you want to keep your money in your home country bank and you plan to return to your home country every 1-2 years to apply for a new OA visa.
You get a 1 year extension of your non O visa at the Thai immigration office. You can extend either as retired or as married. No need to leave the country.
You might consider keeping 800,000 in your account the two months before to apply for the next extension. If for some reason your attempt to use the monthly method is unsuccessful then as a backup you can continue with the deposit method.
Depending on the immigration office you can apply for your 1 year extension 30 or 45 days before the extension expires. You do have to be here in that time window so pick your 1st extension month to be convenient for you to be in Thailand.