Your reasoning is correct. But I think that in this context the meaning of 立つ is "to stand still" rather than "to rise".
に doesn't function as a particle of destination but as an adverbializer (look the last entry here. It modifies the verb, it tells us how the verb is performed.
So in a sentence like:
それ is the subject who stands up (立つ) in a way that is helpful (役に).
You may have other aditional に particles indicating time, location, etc.
Have in mind that the subject is not always what marked by は. For example:
Meaning: As for me, (it) is really helpful.
The subject is always marked by が, but when it is not present you'll have to deduce it from context.