When opening a json file using it's -ts-mode, bread-crumb-mode causes a big performance impact. This performance impact seems to be more than linear i nrealtion to file size, doubling in size causes more than doubling the time until emacs becomes responsible again, likely because it contains more than double the number of nodes to parse.
Many other popular editors contain a breadcrumb-feature and having that feature for json, yaml, xml, ... files seems "natural".