Is digital delay really necessary for broadcast?

Then:  No.

Now:  Probably.

Why?  Because contemporary broadcasters and athletes have none of the "holdbacks" in language that they should. It's got nothing to do with HDRadio. It's just that whoever's got the mic hasn't got got the good sense to keep their language inside polite bounds.  And that's sad.

From Tom Taylor:

A 20-second delay during radio broadcasts of the Cincinnati Reds really annoys the fans.

Half of that is the standard Clear Channel delay to give somebody back at WLW (700) 10 seconds to bleep out offensive language by players or fans. But the Enquirer’s John Kiesewetter seeks out WLW sports operations director Dave Armbruster for an explanation, and Kiesewetter says “the processing and compressing the signal for digital high-definition broadcast [HD Radio] caused the longer than usual delay this year.” Armbruster says “we’re well aware of it, and hopefully by the weekend we’ll get it down to a reasonable 10 seconds or so.” Radio stations have been encouraging fans to “take your radio to the ballpark” for decades, and a 20-second delay might make them think they’re in the wrong ballpark. Reds team management is now aware of the “obnoxious” delay. The Reds depend on the WLW feed – they even “pipe the Reds radio audio into the restrooms”, says Kiesewetter.