And yet both have done it since. Godspeed, as you mentioned, also has copied some of his powers.
When it comes to Flash powers, ultimately whoever is the main Flash will have access to that ability unless it's plot relevant. Impulse is tertiary at best right now, ergo if Williamson wants Barry to have Speed Scouts, he will. Fight it all you want, this is how DC operates. You tell me I'm wrong and then provide examples that essentially prove I'm right. When needed, the "main" character of the IP will inherit the abilities farmed up by their supporting cast.
Yeah, Nightwing is twice the aerialist that Bruce or Barbara will ever be, but they won't likely slam their face on pavement and think "damn, Dick could have made that." They usually get by just fine and Nightwing's superiority in that field will only come up when the writer really wants to remind you of it, but it rarely holds any significance. DC has done very poorly in the last decade at letting the sidekicks and supporting cast shine because it absorbs their relevancy into the primary IP in an effort to make it stronger but in actuality making it more bland.