While many paralegals have experience drafting simple documents, they have not been to law school. One of the common problems people face is that a case which appears simple actually has hidden complications that someone who is not legally trained will not be able to spot.
After reviewing your case with you, an attorney may recommend that you do use a paralegal, if he/she feels the issues are straightforward. However, if you don’t consult with an attorney first, you won’t know if possibly serious complications have been ignored.
Also, a paralegal won’t be able to represent you in court or negotiate a settlement with the other side.