Most of them are specifically artillery shells.

Nah, but the Russians took massive losses at some point last year (I seem to remember) because the Ukrainians launched a bunch of mines behind an attacking column, so that when the column was beaten back, they ran straight into a newly placed mine field.

My impression is that remote mining is used for two purposes: Defensively, you can break up or slow down an advance by suddenly laying mines either in front of, in the middle of, or behind, an advancing column (the latter preventing reinforcements from arriving, or the attacking force from an orderly retreat). Offensively, you can use remote mine laying to cover the flanks of an advancing force, or prevent reinforcements from reaching a position you’re attacking.