It really changes the economic decision between buying on the internet and going to the store.
Why pay an extra 20-40 dollars per order for shipping and taxes?
Most online stores offer free shipping, or reasonable shipping.
Seriously, if you're buying a new iPhone you get free shipping, you'd have to pay 6% (WV) tax if you purchased online. You can order it anywhere, have it sent straight to your house. The other option would be to get in your car and drive, park, go in the store, get what you want, pay that same 6% tax, drive home, etc.
This bill just is incredibly unfair to small online stores, in the $1m-$5m annual revenue range. Big online stores like Amazon, Walmart, etc have an advantage, they have the resources to deal with the nationwide sales taxes. Small business brick and mortar have an advantage to in that they only have to focus on taxes in one state.