Boxes

I don't know about potential buyers, but they certainly have value to you. You need them to ship the speakers.

I would say that original boxes or crates for a buyer.are very important. Boxes can be expensive, 200$ to 400$ is not unusual for factory shipping boxes. Some companies get upset if you have to return the equipment for service and not in original boxes. If not original boxes make sure the items are double boxed?

‘Like you, I have kept all my boxes.

Joe Nies

When I was considering trading in my speakers, the dealer asked, twice to make sure, that I had the original boxes as they'd probably end up shipping them. I'd even go so far as to double box them, if possible. 

The storage space above my car is full of empty boxes. 😄

All the best,
Nonoise

I also keep all the original boxes even thought it's a pain to find space at times.  Last year I sold a pair of Marlin Logan speaker I'd had for 20 years.  The buyer was amazed and pleased that the speakers came packed in OEM boxes.