I was able to purchase convention tix direct from Disney through my husband's conference. The WDW link states that they are for attendees and their guests. Designed to add on to your conference and make it a full vacation for the whole family. We opted to buy the discounted multi-day tickets since they work out to be cheaper than multiple after 2 or after 4 tickets. Be sure to get the will call option if you need to do FP right away, or allow 2 weeks for the mail. We were able to link them and do FP+ with no issues.
MDE shows that they are Convention tickets.
We had to provide the information about his conference when we booked.
My understanding is that these may not be upgraded once you arrive at the resort like a regular ticket could be. ymmv. Someone more expert than me will know for sure.