Why not? Seems like a cop out.

Being able to ask questions to small open models seems.... obviously useful?

Because they don't have a lot of parameters to store general Wikipedia knowledge. They're small. Use big models that have high parameter capacity to store general information. Or build a harness around the small model that searches a knowledge base/internet.

Use the right tool for the job. It's like asking why a screwdriver isn't good at sawing wood, or calling C a terrible language because it's hard to make CRUD apps with it.