Is it OK to use bullet points in the statement of purpose for graduate school applications?
Both Buffy and JoshuaZ raise valid points:


One of the things that [some] reviewers will be looking for...is your basic writing ability.
The reaction [to bullet points] seemed to be all over the place. One person thought bullet points stood out and were great. Another considered it to be unprofessional.


I'll add: Used well, bullet points can convey your message succinctly, which is a skill reviews are looking for. Used badly, they suggest a poor writing style. You, yourself, can perhaps determine whether bullet points are working. Give it a try. You can also ask people what they think.