It is certainly helpful to others, if you submit corrections, but it is not required, and it actually may not affect how it attaches to the person in your tree.
The alternate information will show up, after indexing, when others search for the same person.
For the information to be correct in your tree, you will need to modify what is entered in your tree - on the tree itself, not just on the index of the source record.
Screenshot attached to try to help explain. In the 1900 census, my great grandfather was enumerated as D Burgess Jefferson, while his name is actually Jefferson Burgess. The entire Burgess family is listed as a Jefferson family. I submitted a correction to that record in 2008 - almost 5 years ago. When someone adds that record to their tree today, it can still show up as Burgess Jefferson unless a manual correction is done.
The new Beta attach process sometimes does it better, but not always. [Edit to clarify] If someone has added an incorrect alternate entry, that information may be offered to you to attach to your tree.
Examples of both attach processes in the screenshot - old on the left, new beta on the right.