This is case by case, so hard to determine a best practice
In some cases, "show all" in a list view might confuse users, if they see both quotes and orders
See if it makes sense to the Users
> Is there a best practice regarding this kind of dual-use of tables? Any pitfals to be aware of?
Okay, if there's no glaring "NOOOOOO never do that!" reason why I should avoid this kind of practice, then I'll go ahead with it. The ways most users have to view the data will be locked down, and they won't be able to do a "show all".