My grandmother used to say of certain things that she disapproved of, ‘It’s so unnecessary’. For me, that applies to music added to the soundtracks of what would otherwise be interesting videos, such as ‘Cooking better on gas’.
It is indeed not merely unnecessary but counterproductive. Though often referred to as ‘background’ music it is typically at a similar volume level to the speech one wishes to hear and thus an annoyance and a distraction. That certainly applies to the above instance.
I can understand why music was played in cinemas in the days of silent films. I can even understand why it has continued to be used for ‘atmosphere’ in sections of films where there is no dialogue or other sound important to the action. But superimposing it on speech is nonsensical, especially in the context of a serious technical talk (albeit in the above instance one that is only a series of brief soundbites).
So, on to a query: Why do you do it? Is it just because ‘everyone else does’?