Back in the bad old days the lion, nimh batteries were not so good. Even today there are some that want AA or COMPACT FLASH or have some other requirements. In fact my first over megapixel camera barely hit 100 pictures without having to swap in the second rechargeable pack.
Today you will find new owners that didn't live during the days of film, 35mm and the transition so they'll wonder why you don't get thousands of shots per charge. That's an interesting area in itself.
Let's just say that everything has improved.
I almost bought a point & shoot digital camera which uses "AA" batteries. People I know who have such cameras complain that the cameras are great but the batteries must be changed after about 300 snapshots. That is useless to me as I often shoot 1000 photos at a time. Why have the manufacturers replaced lithium ion batteries with "AA" batteries? The batteries are easy to purchase but rechargeables are much better. I notice that the deluxe models still use lithium ion batteries.