We have never done thank you cards nor have we ever received one (and I live in the south!). I would just make your life easier and skip them. Verbal thank you’s are perfect.
Ditto to all of this!! I always feel like I want to have my kids do them, but honestly its one more item that I don't have time to deal with. My kids are good about saying thank-you in general. Sometimes I might send also send a thank-you text to the parent because usually its someone we know pretty well.