When I got into wrestling (later than most, but still 12 years ago), one of the first things I couldn't understand is why the WWE US/IC titles existed.
When you're a champion, that means you're the best at a certain thing. Best wrestler, best female wrestler, best tag team, best cruiserweight, etc.
Even "back in the day" it didn't make sense in kayfabe. Midcarding isn't a division, it has - especially in WWE - meant you aren't on the level of the top guys.
While since getting away from the E and seeing NJPW where it feels like "oh you aren't on the level of Okada? Yeah cause that's really hard, guys like SANADA are still world class athletes", It still feels like a consolation prize and it enables lazy writing.
In WWE, Lashley REALLY felt like he was less of a star with it. He's holding that belt, so you don't think of him as a main eventer, and you don't even realize how much ass he's been kicking without that golden anchor they had to book their way out of. The best midcard champs I've ever seen (obvious 2015 Cena) were guys who didn't need the belt. I can't even remember guys like Adam Cole with the North American title doing much with it.
WWE had two shows and two brands for the better part of the last 12 years. It's hard to argue that having 1 title for 2 brands with 40 different roster members/show proves anything, the argument could be made in kayfabe that a champion frequenting one show devalues their status as the best. It's a deficit for either show to be without a champion, in the midcard.
The kayfabe function of a midcard title is pretty simple. No matter what walk of life you compete in, there's intermediary accomplishments. You get a purple belt, competing in purple belt competitions before getting a black belt, competing in black belt competitions. It's not a disadvantage for the promotion to acknowledge that the vast majority of their roster is, in fact, not as good as the world champion. It doesn't mean they can't prove themselves, both in booking and kayfabe, to be champion by showing their ability to be the best of the rest with midcard titles.
Also, the function of the midcard titles "back in the day" didn't discredit the reason for a midcard title, either. An example being JCP/WCW which had the World Heavyweight, US and TV titles, in their midcard singles division. The TV title was regularly defended on TV, and on house shows, often given to the guy deemed the best worker or with the most potential as a worker, to test their in-ring skills and endurance. This was also the kayfabe function of the title, this is the workhorse and this is him proving it. The US title was to test the ability of a guy to draw. The Heavyweight champion rarely wrestled on TV shows, or if he did, it was often in one-offs or tag matches. The US champion was the only regular, reoccurring champion to appear and wrestle, on a regular basis. The Heavyweight champion was obviously the top prize, but the kayfabe function of the US title was also very similar to the booking function, that this guy is biding his time.
WWE's poor booking of their titles is more of the issue than the fact that they exist.