That site, shows the prices (in Thailand and elsewhere) by default with tax refunds. I presume that to be the tax refunds for short term travelers in that count

That site, shows the prices (in Thailand and elsewhere) by default with tax refunds. I presume that to be the tax refunds for short term travelers in that country who buy things there, and not applicable to ordering online from there and getting it shipped. AFAIK, a few countries (including countries like Australia and Canada) have such tax refunds above a specific amount of spending for some specific categories of spending.