I'm assuming that they removed this because of the potential to use marks in order to earn reputation, essentially. You could use marks to get materials, and then use materials to get rep, therefore resulting in much more rep gain for people who don't need marks for anything anymore. Frankly, I think this was a good change, and it was what the majority of players wanted. Myself and many others simply used our marks on legendaries just to dismantle then for ascendant materials (that we didn't even need), which I'm fairly certain was not the intention, so this is a good change for those players. That's not to say there are people disappointed, but you simply can't please everybody. As an example, they patched the raid exploits. Were people upset? Yeah, of course, but it was the right decision, and it had to happen. Same situation here, in order to please all the players, they would have to include both the transactions, but this would upset the balance and be an exploit that ultimately leads to shortened play time. Bungie knows what they are doing, although it might upset some, most of their choices are for the best.