Not nonsense at all.
Crappy alarm will waste £150-200 of your money, offer zero real protection other than potential bellbox deterrent and more likely to false alarm than real alarm causing neighbours to get pizzed off and ignore ahy alarm in future.
adt box will cost you minimum £70, will still just be a lump of plastic and no more recognised by billy the skaghead chancer than a Yale at £10.
Thats why its a rubbish choice, for sure, but I would 'recommend' a Yale dummy over a working 'response' any day of the week to anyone without the budget for a proper system. On here, that is, of course.