Letting your toddler fill glasses, etc. is like refactoring. It costs way more time now than filling them yourselves but if you don't ever let them do anything, you'll find yourself in a mountain of technical debt with a child who is incapable of assisting with any tasks.
More than that, you might find yourself with child who lacks a sense of self-esteem and self-agency and struggles with these things even into adulthood.
