I suppose 'every bit helps' but, in a nutshell, 'no'.
Having reported my bike stolen and having handed in a lost/stolen bike (so I could recover it under finders/keepers rules) I am familiar with the backwardness of the whole Police process of dealing with stolen bicycles.
I also know that 'Datatags' are definitely not what you might call a hot seller in bicycle shops - they might be in the motorbike world but bikers only put them in because they have to be insured. If they were that good then people would be queuing up for them, as it is they just collect dust in bike shops that actually stock them.
The likelihood of your tagged bike being found by the police is going to be slim, only if it gets handed in are you likely to benefit from the Datatag and that is assuming the Police have one of those scanners anyway. I have not heard of these things working - there is a complete absence of anecdotal evidence on the internets too.
That said, I do have faith in the new Bike Register scheme and have my bike tagged by the Police. Most Police do have days in the town centre where they mark bikes up for free.
Given that the scheme is free and endorsed by them you have to wonder why bother with any other scheme, particularly if there is practically no evidence of it having ever worked.
You get stickers with Bike Register and you put all your details with them, an improvement on postcoding.