The above is what Amazon does and I believe they allow authors the option to add or exclude VAT from their price. Amazon handle VAT completely.
The problem is that lots of people don't use Amazon/Google/Apple and they sell direct. They have to implement the necessary code changes to detect and calculate VAT correctly. On top of this, you have to register for VAT MOSS (UK) and then report and pay VAT to HMRC (UK). This is a lot of hassle and believe it or not, small businesses have been closing because of this.
For us, we had to change our terms of service so that authors and content creators gave us a licence to sell their work so that we can become the supplier and therefore the legal burden is on us to calculate, report and pay VAT to HMRC.
The main reason for this change, which was agreed in 2008 and came into effect on the 1st of January 2015, is to stop companies like Amazon, Apple, Google and other large companies from enjoying low taxes as they base their digital services arm in Luxembourg. For ebooks, they enjoy a low 3% sales tax. A very nice loophole for these large corporations but it has rightly so been closed.
The knock on effect is that small business and retailers have to deal with this new EU VAT change too where VAT needs to be calculated at the customers location rather than the sellers location. Once they do this, they then need to report it to their respective government. This adds a lot of administrative burden on small sellers that are barely making any sales.
The most important thing that the EU could have done which they didn't do is to have a threshold so that small business and individuals aren't affected. Recently, Japan introduced a similar change but maintained a threshold to protect small businesses: http://www.vatlive.com/asia-pacific/japan-consumption-tax-fo...
The EU VAT change is an unnecessary burden for small business and individuals which is why we handle VAT completely for our customers.
Lots of use cases. For example, I use Stackoverflow a lot and I need to paste code rather than faff around with pastebin. I can see myself using this to get a gist URL in one click.