do you know if you have low stomach acids?

""Do you think enzymes are useful?""

Yes, they are necessary for the digestion of food.

""Ive read we run out of them.""

Thats right, As we get older our stores of enzymes get depleted.

""So even if we heal our liver, that would mean we still need enzymes.""

Right again. Enzymes are found in uncooked food. This is the source. If you don't want to deplete your supply, (and you don't want to or you will age quicker) then its is necessary to eat raw food.
Some of the healthiest, longest living people on earth live on raw foods (live foods).
Enzymes have a lot to do with it.
There are no enzymes in cooked food. They have been cooked out of them.
If you want to ensure that you always have a healthy supply of enzymes then don't eat cooked food.
If you eat cooked food, the body has to dip into its reserves for the enzymes.
If you eat raw food, the enzymes are right there in the food itself.
Its kind of like if you have a savings account you don't want to live off of it, it will get depleted.
Thats why we like to have a steady income, we can live with the money thats coming in and still have our savings. If we deplete our savings then it could spell trouble.