As others said, digital is great for calipers, but it's kind of a problem with micrometers. Machinists and inspectors very often prefer vernier micrometers. One of the main advantages of digital is ease of conversion from one system to another, and so that's why it is nice to have digital calipers, but for really accurate things, one reason among many to have a manual micrometer is that you have already done your conversion or only use one type of measuring system in a given shop, usually to match your machinery, and they are more reliable than digital micrometers.