Does a longer digital caliper read any finer?

Resolution is only the smallest step the screen shows. Accusize quotes ±0.03 mm accuracy for the yellow-screen 1110-1818 and 1110-1828, three times that step. The collected sources give no accuracy figure for the other eight, so you can't tell whether theirs is looser or tighter.

It changes even within a line. The yellow-screen 1110-1818 runs on a CR2032, while its longer sibling, the 1110-1828, takes a CR2025. The 3-key models and the left-handed AB11-L106 use LR44 cells, the IP54 metal-cover pair CR2032, the fractional pair CR2025, and the IP67 1199-W616 is the lone SR44. No. All 10 Accusize calipers here read to 0.01 mm, from 100 to 300 mm, so length only sets how big a part the jaws can span. Six of the 10 are 150 mm, and that size carries the extras, including the fractional-inch 1110-0818. 1110-0838, at that maximum range, is the one other caliper that shows them.

Three, going by the names and titles. Accusize's page title calls the IP67 1199-W616 water resistant, and the 2015-0150 and 2015-0200 carry IP54 in their names. The other seven don't name an ingress rating, which could simply mean it isn't stated.