The statement made was about what we assume is the purpose of the material world, not whether we use it for our own benefits. Here it is again:
And like I said, I don't assume the purpose of the water, gas, or electricity is simply for my enjoyment. Do you?
The purpose for which we use something is connected to that we believe about the purpose of existence of said thing.
But if I did that certainly wouldn't mean I believe all chocolate exists just for my enjoyment.
There's a lot of gas, water, and electricity that exists that I will never use.
Like I already said:
The empahsis isn't on those conveniences pleasing just you and nobody else; but on pleasing.
IOW, you hold that material conveniences eixst so that you, other people, other beings can consume them; and more than just consume them - enjoy them.
Of course, given that you probably resent that things can be stolen from you, and probably resent power shortages, rising prices of gas and electricity etc., this would suggest that you in fact think that those material conveniences should exist so as to please you (and not the thief or people with lots of money who can readily afford higher prices).