I see a lot of hand-done splices that are buried to get the mark in, but still could go an inch or two more if we put just a wee more force on it. If you're using the whipping as an overload indicator, you might be led to assume a splice was overloaded when really, it was just the first time it was loaded to 1,000 pounds or something like that.
Personally I prefer invisible stitching because I know the stitching fibers are protected from chafe. I've seen climbers with lines that have NO whipping but you can see where the whipping USED to be. When you ask they tell you it fell off. And now they have NOTHING?!?! Eeek!
The visible whiplock does give piece of mind. That's true. But for me, I know that once it leaves my bench, that means it has the invisible stitching. It's good for life.
When I splice for competition climbers, I put the whippings on it because the judges will DQ it without the whipping.
love
nick