I use my Thai ID card at the bank when transferring large sums of money from the UK, I was asked for my passport when I went to hospital and showed them my ID card instead, I have used it when checking in hotels. It saves carrying a passport. What's not to like about it?
Don't buy a motorbike in Thailand if you value your life. Buy a big pick-up truck. If you can't afford one you should not be living in Thailand. Simples!