I do not dispute the need for a sufficient total amount. I consider smaller containers more comfortable though. They are easier to keep in reach, the water doesn´t slosh around as much as in a half empty big container and if foraged water needs treatment it can be done in an empty container instead of having to put it in a half full container with clean water brought along.
Along that line of thinking owning 10 bottles is not excessive. I own a similar amount. Most of them are kept in their place just in case (e. g. the car, my EDC backpack, in my motorcycle´s trunks). There were many occasions when they made the difference between staying thirsty and keeping hydrated. I might own more if our climate was more arid or the distances were longer.
Carrying them may be overkill in some situations and not enough in others.