Simple example, displacement zero but distance travelled is twice! A step before, if you touch a piece, you will have to move that piece only. That’s the rule in chess! Funny example can be, you called someone to visit home, now you cannot roll back and replace! That’s Chess, super sharp, super focus, stay committed – any time, every time!
Pawn move in chess is referred as committal as it can’t be taken back or reversed. So, be careful when you move pawns! Oh, that reminds me, World Chess Championship where the challenger Nepomniachtchi lost 3 games with pawn blunders against World Champion Carlsen! Also, special moves like castling (king & rook movement) and en-passant (pawn capturing other pawn if it cuts in its 2-step advancement). Please do study these topics, very interesting to develop sound chess basics!