There are zero special tax regulations or allowances for Thai Elite Visa holders. Their statement is misleading people into thinking there is, or a marketing spin at best.
Yes, some DTAs can impact a Thai tax resident. And yes, there is some transitory provision regarding money transfers before 2024. In some circumstances, an elite visa may make sense in someone's tax strategy compared to that of their home country.
The government should consider aligning Thai Elite revenue allowances with the LTR. It would undoubtedly make it more attractive to higher-worth people. But TiT and who knows what vague tax ideas will be wafted out in public before any tax reform will be firm in future years. Until then, the only solid thing is the actual RD tax provisions - and concessions for Thai Elite Elite visas do not exist right now.