My digital caliper is a cheap piece of junk, but it still does the job well enough. People who have never worked in precision manufacturing have no idea how much work there is, or how easily it can go wrong. My drafting instructor had a large aluminium block that had 95% of the original material milled away for a fancy housing, and it had to be scrapped because just one fastener hole was outside the specified tolerances. Now it's a paperweight and classroom demo about the importance of tolerances. Loose parts, though? That's scary stuff!