Bank transfer is slower with a poorer exchange rate and so you would get significantly less money in your account and have to wait longer for it too. I'm just not sure if Wise is marking funds as International transfer currently which you need to show in your Thai account for visa purposes.
You can buy a temporary verifiable onward ticket online for just a few pounds / dollars at Best Onward Ticket (others are available) for your own peace of mind. It's valid for a couple of days and then gets cancelled automatically. It's a real ticket with a PNR number which can be checked by airlines, immigration etc.