Brian - thank you for a very informative and well explained reply.
It makes a lot of sense - there is no advantage to be gained from an electronic level, as it still just displays (like a conventional bubble level) that the rifle is being canted. It gives no other feedback whatsoever, and does not imply any corrections or any corrective action to be taken, other than to indicate you're canting the rifle - same as the bubble level mounted to the gun. And pretty much the same as a thread of wool hanging from the rifle "telling" you the wind is blowing in a certain direction...
As far as an electronic sidewheel which makes corrections on your behalf, I also agree with the reasons as to why it would not be allowed - almost like a Kestrel wind meter telling you wind direction, wind speed and even giving you the "clicks" to adjust for the wind (like on the ballistic models).
Anyway, glad it's cleared up.
See you all in Portugal.