I don't think it is a useful feature.
Solid Edge already has a built in spreadsheet-like UI that has all the controls you would need to create, edit, and modify a family member. Depending on the integration of a 3rd party spreadsheet would only create havoc with IT systems, upgrades, licensing, etc.
I have the need to create some fop and foa that has around 1000 family members. Do you thinks that it's easy to make in that spreadsheet-like UI? In excel we can have the capabilities to copy past certain cells, create formulas. In my opinion it would be a lot easier to create them in excel. That user interface is fine for 10, 20 family members, but when we start to increase them, it's chaotic... Notice that almost all of the other competitors use excel for this, it must be a reason!