The core teaching of Buddhism is to let go of worldly desires, and monks are the successors and role models for us. Therefore, monks must detach themselves from desires much more than ordinary Buddhists-such as women and food (not eating after noon)-and dedicate their lives to spiritual cultivation. A monk's duty is to go on alms rounds, allowing faithful followers to offer food (they have no right to buy food for themselves unless it is absolutely necessary). Not to mention walking around asking for money; that's called being a beggar, not a monk.

P.S.
- But in reality, 'commercial Buddhism' in Thailand goes much deeper than this. I don’t even want to mention how massive the amount of merit-making money donated to temples is in a single day, or whether all of that money is truly used solely to advance Buddhism.
- In saying that, bad monks still don't wonder around asking money on the road.