I have no idea how they expect to make this work!
From a software developer's perspective, taxes are a major PIA. In my own software I've had to code for separate tax laws in 50 states, 10 provinces, and six countries. Some of the rules are really goofy (lookin' at you, Quebec and Florida).
Now small businesses will have to get tax forms and instructions for every locale they do business with. Not just every state/province/country, but the hundreds of taxing districts within them (every city has its own tax rates).
They will need to alter their bookkeeping systems to create accounts for hundreds of taxing authorities. They will have to figure out how to calculate the taxes (some locales have a sliding rate schedule depending on the amount of the sale, some have complicated rules about what rate to use and who and what items are subject to them, and a few oddballs have compound taxes).
They will have to identify every customer's precise locale to determine which taxes apply, and ask previously-unneeded and intrusive questions - like "do you work for the government?", "are you a member of a native tribe?", "is this for resale, and can you prove you have a business license in your state?".
This was not an issue before, because taxes were based on where the retailer was located, not where the customer was. Amazon has always charged me sales tax because I'm local to them, and it has always been the tax rate for their home address in Seattle. Sweetwater does not charge me sales tax because they're in Indiana and I'm not. Now, Sweetwater will have to somehow know what taxes apply here in my hometown, get updated when they change annually, and file returns with the state of Washington. And every other state and province they ship to.
Years ago the state of Oregon wanted to collect liquor tax from airplane passengers flying over their state. That idea didn't fly, for obvious reasons.