So, you would prefer to
a) print out the plates for every possible diversion airfield along the route (say, 10kg of paper)
b) go flying with just the dep dest and alt and hope nothing unexpected crops up?
c) subscribe to, and carry, and regularly insert the updates into, the printed Jepp subscription?
Certainly, seeing as I've answered the question in detail twice now, you ask rhetorically. You can read.
The Jepp UK paper binder alone is huge. A European flight of say 800nm would involve carrying some 20kg of Jepp binders.
I'm familiar. I maintain a world set, plus military.
"Certified" means very little. Anybody can get a TSO for a piece of junk - just takes a lot of time and costs a bit of money. I've seen plenty of defective design avionics which is TSOd.
A TSO is a Technical Standard order which prescribes a level of function from a given device or appliance. It's nothing more than a standard. One does not "get a TSO" for one's equipment. One builds it to conform to the TSO. You may be thinking of a STC, a supplemental type certificate, which has nothing to do with TSO conformity.
Various classes exist for EFB's, each with their own relevant technical standards. Someone who elects to pick up a used tablet on ebay and roll their own, and then use that equipment as their sole nav source, would be asking for trouble. Clearly.
They also wouldn't be legal.
Printing at a minimum one' departure, destination, and alternate, and carrying a paper set along, is a simple task, and should be the minimum standard.
I wouldn't get too worked up over having to maintain just Great Britain in one's charts...it's just not that much area or that many approaches to maintain.