I am a control system engineer in the energy industry - and have been since 1979, so obviously IKBA applies.
They were introduced as a political gimmick, to make the populas think our lords and masters were concerned enough to be seen to be doing something about poor energy use.
There is no compulsion to have them fitted, they are not fitted free, EVERYBODY pays a hidden surcharge on every energy bill, which goes to fund this stuff (as well as RHI payments, loft insulation, yarda, yarda, yarda).
The more 'stuff' an 'energy provider' can install the better they meet their 'targets' and the more they get paid.
Would I have a smart meter - NO. Would I find out 'stuff' about energy consumption instead - absolutely.
Why - there is not one common protocol or software calculation set used by all AND there is not a single letter of legislation that governs the accuracy or anything else of any of it (unlike the actual meter for the reading that they bill you by), in previous times at least one make of meter has been withdrawn because it was found to be "not accurate" - nuff said.
Switch energy provider and you will more than likely have to switch smart meter as well, then you cannot actually switch provider until the previous provider's smart meter has been changed.