I'd say that in the PPM world you need the identifier even more for several reasons:...even in a PPM market. Just because you dont NEED to identify yourself with the meters, it doesnt mean you shouldnt.
First, the world is filled with options. If you did a good job of satisfying a listener's needs when they last listened, you want them to know where to come back to. A jingle does that (and it should identify the name used across all distribution channels, whether radio, streams or audio aggregators like our friend Alexa).
Knowing where to "come back to" is critical in the PPM world, where "all day listening" is really a bunch of 10 to 20 minute bits and pieces and where you can loose a listener at any moment.
Second, you want the station associated with its brand of music. So playing a jingle next to a big-testing song gives your station a subtle "ownership" of the song itself; call it "guild by association"!
Third, jingles wear better than recorded voice liners and sweepers. In many cases, a simple acapella jingle does a better job than anything else in those cases for many formats.
Of course, some formats just don't work with jingles... Alternative Rock comes immediately to mind. But most formats do, if the jingles are short and fit the tone of the station and its music.