It seems that their sockets and ring spanner have the corners rounded out so they only make contact with the side of the nut rather than the corner - a clever idea I think !
Quite common on better quality tools, though everything has its place: the cheapo nasty socket set that has sockets with 12 very sharp points inside are actually really good if you've rounded a nut off - select the next size down socket (remembering of course that the next size down from a metric might be imperial) from the proper one that the nut is supposed to be, and hammer it onto the nut. The sharp splines will grip it well and may be all you need to wind it out
The price though !! I can get a set of comby spanners in my local Lidl for 1/2 the price of a single Snap On spanner.
Should DIYers bother with them ?
Buy cheap, pay dear. The quality will be remembered long after the price has been forgotten!
The set of spanners in lidl that are half the price of a single snap on spanner are probably made of cheese and will ruin more nuts and make your job harder work.
I bought a cordless and impact driver set from Aldi, their premium range (yep, aldi have a premium range), and it's quite a good set. It also has the advantage that noone on a site would ever nick it, and the batteries don't fit anything else (batteries always walk) but it has its limits, and it's mediocre DIY level in terms of stamina and strength TBH. It was good for the time when I was just starting on doing a bit on site and wanted my own gear but pretty soon the other trades moved on and I was more and more of a mind to build my house myself. The Bosch cordless+impact set I got 6 months later was twice the price but easily far more than twice the tool - the cordless will zap screws in on price work mode (gear 2) that the aldi one struggles with on day work mode (gear 1) and the impact driver will keep winding until the bit explodes or the screw disappears through the work whereas the aldi one is forever complaining about excess current draw from the battery and shutting down when the screw's only a third the way in.
Cheap tools have their place: start out with them, as soon as you discover its limit (i.e. it breaks on you or plain up doesn't have the balls for the task) replace it with something more expensive. I still have a Kamasa socket set, but it has a Teng ratchet handle that is worth more than the rest of the set - the original kamasa ratchet dropped to bits quite quickly and understandably so - it's a complex mechanical thing compared to a socket so it's asking a bit much to get a good one, and 50 sockets for 30 quid