Actually it is not a mistake. If you notice our new platform is compatible with Reention. It fits right on and we did this very deliberately. So you could in theory call Reention and get a Dorodo Plus case, then have the cells welded with the lithium flavor of your choice and it will work on the bike.
On top of this the connection to the controller is XT60 which is an open standard. So if you ever want to install your own battery pack. It is really easy to do. We very much did not have to make the electronics this accessable. But we want to make sure the bike can be repaired many many years down the road.
We understand the need to do this because our very first product was actually a battery pack for the DIY market in 2009.
https://endless-sphere.com/forums/viewtopic.php?f=4&t=12961
Some of them are still running today.
The reason we made our own packs is that we can add many features which cannot fit in the generic OEM battery case such as the GPS or a 45A BMS and 52V (14S configuration). There are also some other reasons which will make sense later.