Don't really know how to explain it, but I do think that, say, for a short radio interview, a voice-over artist is more likely to be asked to give a snippet of one of their 'voices' than a singer would be asked to sing something. For a start, lyrics are all in context. Everything slots together. So, a singer/band would need to at least sing a whole verse/chorus for there to be much point in them doing any singing at all (unless they were doing some demonstration on a unique aspect of their voice or something). But then, again, what would be the point for the show in that when they will only have a set slot for their guest/s and will already more than likely want to fill that with their questions for them, etc? You do tend to get a record or two played at points during a interview. These give both the interviewer and the musician a break, though, so you wouldn't get the guest singing in these. Oh, and the 'breaks' are also there to ensure the playlist records for the show get played in full...and that's a lot of records to play.
Also with musicians, particularly if they are being interviewed just for promo on their latest track, their record will almost certainly be played at some point during the show they are on. So, even though something from a studio track and a singer singing 'live' are different, it could sort of feel like repeating themselves for an interview for which they've only got limited time to conduct everything in. Obviously you have loads of live music on the radio, with extra time put aside for this...but then, that's part of the point: the time. For simple interviews that have to be crammed into a show with so much else on, there's only so much time to get their questions into as it is. Again, though, if you've got a dedicated slot put in for an artist to do a live set, then things become different again.
It's quicker/easier to organise to have a voice-over artist do a snippet of one of their 'voices' or 'characters' than it is for a singer to sing a whole song (with all the 'sound' and set-up needed for a song to come well). So it's more immediate with a voice-over. And there may be nothing at all to organise if it's simply an off-the-cuff response to something. Maybe the most you'd have to organise is one question. You can get a good idea of how an accent/character voice sounds from a brief sample of it. So it's not so much about context here. And as this sample would usually be in response to a question, then it is still the interview that's going on. It's nothing any special time has to necessarily be set aside for.
And as with Chris today, the 'voice' he put on was a nice rounding off of the interview.
I personally love, when I get to hear them, the live lounge's on Radio 1. With these you get both chat and a live set (a latest single and a cover version). That's a really nice mix.
Then there's also the difference between the music industry and the voice-over industries. I suppose the voice-over world, though deserved of much respect, and though filled with many talented people, may be seen as more of a specialist industry - one that doesn't filter into people's consciousness as much as music often does. The promo for both industries is disparate, and they are just mediums that are too uniquely individual to end up having the same reach.
So, you have less voice-over artists than music artists actually talking on the radio in the first place. So then, for me it then follows that this seemingly more (for definite want of an accurate word) 'niche' industry has more value in its demonstration in the constraints of one brief interview than that of music.
Told ya I didn't know how to explain it...
And on Chris's interview, thought it all went very well, but thought the build-up to it was sort of the wrong way round! Up to the first point we first heard very briefly from Chris, there'd been nothing at all on the show to say who they would be talking to on voice-overs (well, apart from the fact it'd be common sense for someone to assume it was someone who knew a bit about voice-overs!), and then suddenly it was 'Hello, Chris', etc. We know who Chris is, but it was like all the listeners were meant to know who he was. Then when the main interview started,
then we got a little intro! Odd!
What a long post! Um, better out than in...or something...