Anonymous participant embassies will not process a visa application if your application states that your planned entry into Thailand is greater than 3 months from when you apply.
KYC. Know your customer. It's why so many people's accounts were frozen and why anyone's bank account is at risk if they don't meet the current bank requirements to keep a bank account. The bank will periodically ask you for your documents showing that the person using the account is who they claim to be and will reverify everything.
wants to be 100% sure they will accept his foreign license without requiring things like an embassy certification, certified translation, or anything else, then having an IDP will greatly benefit him. Especially if he runs into any issues or isn't able to get the Thai DL right away, then he can still drive legally with the IDP. The IDP can also make a difference as far as being required to watch a video or take a written test at some DLT offices.
I would definitely recommend getting the IDP from home before traveling to Thailand. It gives you some breathing room and many DLT offices do like to see it.