Well if you apply on digital nomad pathway you'll need to provide income proof. If you go on soft power which means cooking classes or Muay Thai training or medical treatment you don't need to. All depends which pathway you select on your application
This DTV visa is basically a way to get whomever wants to stay in Thailand for up to 5 years as long as they don't work in Thailand for a Thai company. Not so complicated to understand. The government is benefiting from it regardless just by people enrolling to courses and training and spending money on accommodation and other expenses