Is IPN needed for simple donations?

Just installed Fundraising plugin, but now realize it is asking for it’s own IPN setting from paypal. I am using gravity forms for this client already and therefore have the IPN set up for that. I noticed some support threads, but it seems like those were from a few yeqrs back.

Question is:

Is IPN still necessary if we are only doing simple donations (non-recurring)?

Please let me know. thank you