The Hobbit is a really nice book, but it is quite different from LOTR. It will not prepare the reader for LOTR, it is more entertaining than serious.
There is all the necessary information about the events of The Hobbit in LOTR, so one does not have to read both books to understand the events.
And I know some people (rather young people
) were disappointed with LOTR because they expected the same jolly book about adventures where nothing really bad will happen, and got a serious book about life and death and duty instead.