It would be useful to have a button that automatically logs 0.25 liters of water when clicked. This would make it extremely efficient to track total water intake for those who drink out of a glass throughout the day.
Just create a recipe of .25water and use it?
You definitely could add 0.25L of water per cup consumed, which is what I currently am doing. It would save time for those who consume lots of cups throughout the day though - having 20 total cups of water would mean a dedicated button would be much faster.
Additionally, it would be useful if there were 3 or so customizable buttons where users could put in a custom frequently consumed food and use them over and over.
I would go a step farther... much like the water reminder app. I would make it so your entries can be customizable to the Oz/L.... and also be able to sync back to samsung health and other partner integrations.