No it's pointless being registered. Most of what I do is bulk buy and sell. So every sale would have to have an invoice that I would have to create. I would then have a lot more accounting to do no matter the system (I currently use Freeagent) because when you are VAT registered it's not about what is in your accounts but what the invoices say. So I sell an item on Amazon and ebay, I write and invoice for the buyer, but I get the money minus fees so I then have to track down every last document and have to start including money that I was never paid that has to come off the final value for: ebay, amazon (who would collect VAT for me apparently), paypal and stripe.
I'm not sure how all of this works in practice as now I go from just marking money arriving as a sale to a load of paperwork and then I need to get more paperwork to show that some of that money on the invoice never actually hit my accounts. So basically there would be the real money and then all of the invoices going both ways for everything. A lot of work, an awful lot, for what? to add 20% to my markup and give it to the government, or loose 16.66% off my markup and all the work.