Is the idea of this cable that the little nub stays in your phone at all times? No idea if this is safe but I would lose pieces of that within hours lol. Neat concept though.
Generally from what I've seen, cables that are safe are usually listed as being either 'Apple Certified' or "MFi certified'. Seen as this lists neither, I wouldn't buy it.
The below link shows you what I mean by the certified part.
I have no idea about those specific cables... the glaring issue, IMO, is the lack of MFi certification. Of course, Apple will probably never certify a cable of this type... again just my opinion.
For my money, it doesn't necessarily need to be a cable from Apple, but it must be MFi certified, at a minimum for me to consider it.
I have had MFi cables throw me the "this cable is not supported" error before. In fact, my wife just got that on her apple watch (the only cable she has came with her brand new watch straight from Apple). Just food for thought on this. There is obviously a risk. But the lack of certification doesn't automatically mean it is unsafe or bad.
I would never try them. The risk to such an expensive device for a little convenience seems too high, especially since the cables are shipped directly from China. (But, then so are Apple devices. )
I rarely use Apple cables because they're so short. But, the iXCC & Anker brand cables I've purchased are MFi certified and had many positive reviews before I purchased them.