VCF is, in my opinion, one of the nicest file formats in bioinformatics. It encodes the minimum amount of data needed to identify a variant call by default (unlike SAM for alignment, cough, cough) while being flexible enough to allow for complex chains of information to be encoded if you're dealing with structural variant types of data. The "chain of custody" provided by FILTER fields and metadata lends itself to repeatable algorithms for variant calling. Plus, the spec is really clear and helpful.<p>It really surprises me how few tools take advantage of VCF for saving variant calls. As I recall, only about 1/5 open source variant callers that I tested (this would have been mid-2021) actually spit out results in VCF. Other contenders were TSV and JSON outputs.