Like the price, like the size.
I don't like that the cheaper gadgets like this appear to use non-standard connectors. That usb cable seems completely unique, not mini-USB, micro-USB, USC-C, or any other common format. If that's true, it means you need to hold on to that specific cable for dear life, as a replacement means dealing only with these guys, instead of Amazon or any random electronics store. We've run into the same issue before for cheaper gadgets that the kids have had as gifts (chargeable toys, watches, etc.).
Edit - maybe that is a mini-USB port, it looked a bit strange to me blown up to that size, but looking at some cables I have around here, it's possible that it is that standard, in which case I retract the comment!