Huh? this is used because if you are below 10,000ft you don't care how much higher they are climbing
Do Dash 8s cruise below 10000'? If not, using your logic, they needn't make any transmission about climbing as we can all assume (a)they are going to climb and (b)they will climb above 10000'. If you're going to bother transmitting then make it professional and say to which flight level you're climbing otherwise you do, in my opinion, sound like an ego-stroking prat.
Meaningless calls, such as those, just engenders poor practise and leads in turn to such crass calls as the Kingair that I recently heard; "......descends from flight levels....". WTF! A complete tosser letting us know he's been above 10000' and that he's now descending. How on earth is that meant to help anybody? That's the sort of crap that results in people making up their own ways of doing things, rather than sticking to the scripted way of announcing level changes etc.
I have to say I am ambivalent about the wake turbulence call. It doesn't take up significant air time and I do agree it would be useful but so long as it was used when warranted. If a Dash 8 wants to give the 'heads up' to a light aircraft following him in the pattern then I think that is sensible but you know how it will develop; every driver of anything larger than a 172 will be 'cautioning' every other aircraft and there will even be the Dash driver saying it on every single transmission. Targeted calls are okay but ego-strokers, like the 'up to flight levels' brigade really need to get their heads out their arses and realise that not all 172 drivers are inexperienced numpties.