Time with your phone is spent. Time with your grandparents is invested. Both disappear, only one gives something back.

Hours leave whether you chose them or not. The difference is what stays behind afterwards: scrolling leaves almost nothing you could describe a week later, while an afternoon with someone older leaves a story, a skill, or a piece of your own history you did not have before. Same hour, very different residue.

Trade one evening of scrolling this week for a visit or a call. Keep it short if short is what you have got. Half an hour counts, and it tends to be the half hour you remember.