Mut’a is just a sanctification of the boyfriend/girlfriend relationship.
However, unlike boyfriend/girlfriend relationships, (a) a wife cannot just break up with her husband when she wants to, as she's still under contract, (b) there is a fixed endpoint to the marriage. There's also the matter of a woman guarding her modesty and chastity. Thus, in my opinion, there are substantial downsides to temporary marriage, so there should be some substantial advantages to offset these.
Question: What are the advantages of a temporary marriage for the female partner?
Al-Islam also says that it can be upgraded into a permanent marriage, and the temporary marriage could be thought of as a kind if trial run.
This gives an opportunity to the boy and the girl in order to know each other more closely and to see if they can live together for the rest of their life and if their personal feelings are sort of compatible.
In this vein, temporary marriage allows the partners to test for physical compatibility. (I'm guessing most women would be devastated if they were to marry a man and then find out their new husband is not attracted to them physically.)
Another possibility I've thought of: It may be beneficial for a career-orientated woman to have a marriage which expires, allowing her to travel to another country for work.
Perhaps I'm missing something important here, or perhaps the constraints are not what I think they are. (I'd also like to note that, as far as I know, there's no obligation to enter into a temporary marriage. If one does not like it, then don't do it.)
As far as I'm aware, temporary marriage is only possible in Shia Islam, and I've seen some unfavourable attitudes expressed about Shia Islam surrounding this topic. Regardless of your opinion, please don't use this question as a platform to denigrate our Shia brothers and sisters.