They ARE Legal here, but I dont like the part about it being Electronic and with a Battery, both can Fail at any time.
Here We can carry a Muzzleloader in a Motor Vehicle Loaded as long as there's NO CAP or PRIMER in it, the Primer Powder is removed from the Pan or the Battery is Not In an Electric ML.
The other part I worry about with the Battery is as you use it the Battery gets Weaker and the Weaker the Battery the Weaker the Charge it sets off to Ignite the Powder, it's Never a Constant Even Ignition and that has to have a effect on Accuracy. I know that if I just change Primers My Accuracy will be affected, so with a New Battery your shots will be pretty constant, but as the Battery Weakens so will your Accuracy and your Point of Impact.