I think hardback books are more durable than paperback books. Hardback books have covers made from a thick cardboard or cloth material, and the binding is stitched or stapled rather than glued. Hardback books can withstand daily wear and tear and the test of time better than paperback books, which are easier to rip, wrinkle and stain.
Hardback books are also more resistant to environmental factors, such as humidity, heat and light, that can cause paper to deteriorate. If you want a book that will last longer and look nicer, hardback books are a better choice.
I think authors revising their older works to make them more modern is a matter of personal choice and the author’s artistic vision. Some authors may feel that their older works are outdated or flawed, and want to improve them or adapt them to the current times…or they’ve grown out of racism, homophobia, and sexism. Other authors may feel that their older works are part of their history and identity, and want to preserve them as they are. As long as the authors are honest and respectful of their readers and their original intentions, I’m fine with it.
That said, both versions should be available.