Is it better to get travel insurance from Poland or Thailand for a four-month stay?

Hi, I'd like to ask your advice on insurance.

I'm staying in Thailand (and neighbouring countries, occasionally) for 4 months in total this year. 2 of those months have just ended, and with them the travel insurance from my credit card provider. Since I need to get a new insurance for the remaining 2 months, I'm wondering if it's better to get one from my home country (Poland) or from Thailand. By "better" I mostly mean the trustworthiness and ease of the potential claim process, but of course the price of the policy is also a factor.

As to the coverage, I just need the standard health-related stuff plus non-extreme tourist activities, like trekking, swimming or snorkelling (I'm guessing there's no policy that would cover riding a scooter without a Thai licence ;))

Would a Thai policy also be good for short travels to Cambodia or Vietnam? The Polish ones offer coverage for whole regions, like "SE Asia".