An interim championship is a legitimate championship. You need a champion to keep the division in track, and if the regular champion is out for well over a year then you need a champion to keep the division moving. The regular champion earned the belt, so it's not just as simple a thing as, "If they can't defend the belt in a year, they should be stripped of it instead of having all this interim title bullshit!" The interim champion is treated as the champion, and look at it historically; can you honestly say that, when Nogueira beat Sylvia for the interim belt cuz' Couture was thinking about leaving the UFC, that he wasn't the UFC heavyweight champion? Or, in a more practical usage of the belt, when Frank Mir was still injured from the motorcycle accident and Arlovski beat Sylvia for the interim belt, then defended it and got promoted, can you honestly say that wasn't a proper use for the interim title?
Look at the Dominick Cruz situation, for another example. He was a dominant champion and went on a run that could have him vie for the title of BW GOAT, but an injury was going to keep him out of action for over a year, and considering how dominant he was and what he accomplished, it's not fair to him at all to strip him of the title, nor is it fiar to keep the division on hold for him, so an interim title was created. Then another injury is going to keep him out of action for close to 23 months (they strip you of the title after 24 months), and it's a definite possibility that something's going to happen to Cruz within that timeline that'll injure him and keep him from fighting for an additional couple months. Can you honestly say that an interim title is completely useless in this situation?
It's not a glorified #1 contenders spot at all, and it's not a make believe belt either. This isn't that hard to figure out. If it's like what Condit did, then yeah, it's kind of lame, but if you consider the fact that GSP had an approximate return date and it was only a couple months after Condit wanted to fight, then it's understandable why he wanted to wait. At that point it's like if he was the champion and there were three opponents that were all equally qualified for recieving a shot at his title, but he wanted to beat one of them more than any of the others, so why not wait the extra couple months to do it? Tito chose not to fight Chuck when he was the #1 contender, but did that cheapen the idea of the UFC LHW championship, or did it cheapen Tito's run as the UFC LHW champion? You can't blame the object for what someone that uses the object does with it.