It can be of -huge- importance in cases of bodily harm caused by products.
So far the UK is part of the EU, and there are rules about product liability here.
The product responsibility lies with the "legal" manufacturer of a product in the EU. If you import something (as a business) from outside the EU, you are the "legal manufacturer" of that product to the law.
So if you had a EU based toy shop and imported a bunch of lasers from aliexpress or something like that, -you- are the manufacturer when in comes to liability. If they caused harm, your customers should sue -you-, not the physical manufacturer, for any damages (reasonable chance of success if the product was inherently dangerous).
On the other hand, if a consumer makes a purchase directly from a non-EU company, that company would be the manufacturer by law, and you should sue them for any damages if you can by any means (good luck with that, go learn cantonese).