Brezn go well with Weißwurst and sweet mustard early in the day or together with Obazda, onions and radish as a brotzeit snack in the afternoon or evening, both together with a Weißbier. Other than that Brezn are more of a to-go-pastry, often as butterbreze.
And although brezn are available everywhere in germany, there are regional differences in how they are made and they are more popular in the south.
Yes, the first part of my answer was rather limited to Bavaria, where Brezn can be part of a meal but not along with Kraut and where Butterbreze is the most popular variation if not part of a meal. Also some fresh cheese with herbs instead of butter is common. Afaik the other variations are more popular outside of Bavaria.