Just remember, these contactless indicators should be used to confirm when something is live, not to confirm when something is dead - there's a big difference. Regarding safe-isolation, you should use an approved voltage indicator complying with GS38 and the correct procedure.
I do however own a more-basic Fluke VDE2 contactless voltage indicator and use it on a regular basis, primarily as a torch but with the added benefit of potentially letting me know when something's live. I think of it as mainly a light-source, but also as an additional safety measure after performing safe-isolation.