This didnt really matter before we started using jsonpb, since failing to part JSON was pretty straightforward to debug. Now that we use jsonpb however more complex type-aware unmarshaling occurs. For example to unmarshal into a google.protobuf.Timestamp you need to use RFC3339Nano, and messing up the format yield an unuseful error message, so useless in fact that its hard to know its actually a value you messed up and it has nothing to do with your json...
This didnt really matter before we started using jsonpb, since failing to part JSON was pretty straightforward to debug. Now that we use jsonpb however more complex type-aware unmarshaling occurs. For example to unmarshal into a google.protobuf.Timestamp you need to use RFC3339Nano, and messing up the format yield an unuseful error message, so useless in fact that its hard to know its actually a value you messed up and it has nothing to do with your json...