I don't expect to get a physical copy for free when I buy a digital file, or vice versa, but I would happily pay more for a package that offered both, especially for favorite backlist titles.
I have tattered paperbacks that I would like to replace; some have been reissued in the last few years in both hard copy and digital form. I chose to buy e-book versions for (mostly) $12.99 apiece; the trade paper reissues were about the same price, so replacing those as well would have cost me about $25 for each title. I absolutely would have purchased a bundle for, say, $20.
The publisher gets more money from me, I'm happy I get a discount--why not offer the package deal as an option?