It's an open secret among air travelers: the cardboard bike box is the cheap and practical alternative to the bike case. If you are traveling to a place with a few bike stores, you can dispose of it on arrival and only pick up a new one from the local bike dealer before your return journey. The bulky bike case can complicate the logistics in the destination country.
The body bag from YT fits exactly over the box in which the direct seller's bikes are delivered to customers. The reinforced corners, carrying handles and wheels sit exactly where they belong and turn the box and bag into a suitcase. Using a box that does not have the exact dimensions of the YT box is therefore not very promising.
Tinkerers can of course adapt their box to the YT dimensions - and repeat the handicraft work before the return journey if the box has been disposed of after arrival. The body bag is particularly interesting for all those who own a YT or, even better, are about to order one, because the body bag is available with every bike with a 20 euro discount, i.e. for 99 instead of 119 euros.