I've made a few online courses. Some hit big (RM20k), some did (RM3k).
The one that did great was SEO101.
Amongst the offer I considered NOT taking up was a Telegram or Whatsapp Group Support.
Here's why
I bought the same course 4-5 years ago. Ever since then when people had issue, they would raise in the group.
The admin (staff) would reply, handling the errors and such.
What the organiser could've done was delete the group after 1 year? - That's enough technical support.
My response was cynical, "you paid for a course (one-time), you expect lifetime support?"
Get real and grow up.
So when it comes to offer, yes, more goodies would sweeten the deal, reduce risks, increases guarantees. However, you also have to consider 5-10% who'd take advantage at every possible angle.
As sellers, product makers, be mindful of your offers.
They might come and haunt you when you least expect.