However, this is all changing now. UK is keen to get rid of regulations it inherited from the EU, making it a much less attractive place to do business with, from the EU perspective. We can no longer assume that companies hosting EU citizen's data on UK soil will play nice and follow the same rules - it will be treated with caution initially, and (hopefully) with eventual hostility towards it, as UK seems to be going full on surveilence mode with government and its agencies having access to everything at all times with no warrants needed.
So yes, it "doesn't matter" only if UK isn't interested in working with the largest trading block on the planet. If they truly want to go that path, then sure, whatever.
This was never assumed under the current deal; the UK was given a grace period, which has now expired, before full enforcement, but on day one it was clear that inspection and/or barring of some goods (particularly food) would be necessary.
Can't send EU citizen data to a data centre in London if the EU says the UK's standards aren't high enough.
> Great Britain is becoming Little Britain. The UK is like a giant Cayman Islands in 2016. They used to be the wise and perfidious grownups in the geostrategic room, but now it's all about squalid, petty things like Brexit, Scottish secession, anti-immigration; British political extremes are thriving and the middle is dead as mutton. They've lost their soft-power by the bucketful; people who used to beg for their wise counsel now ignore them. What do they want -- to be Airstrip One for any creep with a trailer-truck full of cash? I've never seen them think so small.
And a while ago the Tory party's Russian donors problem was in the news, including the son of an ex-KGB Gazprom owner who got a peerage. Whose party in Italy Boris Johnson the then foreign minister went to, alone. God damn, what a corrupt bunch.