I don't like the thought of sitting in my own dirt and think the Japanese have got it right, showering before they get into the bath. Any forward-thinking person should get a shower, as we are all going to be in the position some day when we can't get in or out.
Having said that, my mother, at 97, still uses her bath. Some 20 years ago they had their bathroom re-done and a corner bath put in. As a bath, it's fairly useless, as the ends are vertical - a comfortable bath has sloping ends. But it has a little "seat" in the corner and she finds she can sit on this and wash herself quite adequately. My father, before he died, did, however, need help getting in and out.
I'd love one of those shower rooms, but we have room for a large bathtub and a spacious shower, so we're OK. If there was only room for one, it would be a shower. For a bath, we would then go to the local thermal baths every few weeks. They have rose-themed baths, chocolate, herbs, spices and beer.