Yes, I used ATT-compatible "burner" flip phones with my ATT SIM card for many years. I'll do the same with my StraighTalk SIM.
I must have misunderstood the concept of the topic! As long as the SIM card is functioning, you're good to go with anything that will function with it.
Yep. Can 2nd this. For years I would buy ATT go phones and just flip my sim card to the next one when things happened. Cannot do that now with my so called 'smart phone'. But I do keep a $20 unopened go phone in the truck. Figure I can charge it off the truck / solar panel worst case. I have my phone list in various electronic storage since its not going to be on the burner phone.