Can I use a Visa on Arrival in Thailand if I already have a valid visa in my passport?

The individual is inquiring whether they can use a Visa on Arrival (VOA) for a short trip to Thailand while also holding a valid paper visa for future entry. Responses indicate that the eligibility for a VOA may be influenced by the passport nationality, and while the individual may ask about entering without using the existing visa, the final decision lies with the immigration officer. There are instances where officials have required visitors to utilize their visas despite other options being available.