If you set your grid to Mil/Thou or Inches, pins seem to line up with the grid:
Schematic grid for electrical items is 0.05"
electrical items are wires, symbol terminals, terminal junctions, inter-wire connectors, symbol borders.
This is to keep wiring sane.
0.05" is a reasonable visual grid.
Making a gridless wiring scheme was ruled out. Makes for messy layouts of teminals on symbol borders.
The graphics snap grid is independent.
Changing units does not change the grids. See attached on how to change grid.
Units tell DEX how to convert internal values to display to you, the user.
The PCB does not have a fixed grid.