The purpose for many of us doing DNA testing is to identify common ancestors with our matches. It can be frustrating if you don't have both the DNA segment matching information and the family trees of matches. One has to have both to correctly identify common ancestors. It is not good enough for a person to claim a particular ancestor if we cannot verify the lineage. And we cannot leverage multiple descendants with matching DNA to identify common ancestors without seeing the matching segments. Sharing family trees is important also to be able to eliminate the possibility having shared ancestry in more than one way.
The solution is for Ancestry testers to transfer raw data to GEDmatch and for testers on GEDmatch and Ancestry to share their pedigree information. Learn how to transfer your DNA data from Ancestry to GEDmatch here. I understand that not everyone wants to make their family trees public to the world. You can share your family tree information in one of several ways:
Go to your tree page on Ancestry. Click on arrow next to the tree name to expand the submenu. Select "Sharing."
You can opt to invite by email address (usually the easiest) or by Ancestry user name.
Type email address and click "Send Invites."