Well, I'm not sure what DTR uses but TrueSkillTM was developed by Microsoft Research for use in Xbox Live (in conjunction with Halo 3 and based on "lessons learned" from Halo 2). On Xbox Live your skill itself starts at 25 but it has a high degree of uncertainty that (if I gloss over a lot of math) essentially means you end up with a skill that is 25 +/- 25, so "somewhere between 0 and 50". The display is "the most conservative estimate of your skill", which means your skill is 99% likely to be above that number at any time. That means that your skill is displayed as 0 because it can't be certain what you are.
It's pretty cool math overall. An interesting thing about all the "skill based matchmaking" conversations around here is that Bungie is one of the industry pioneers of matchmaking based on skill, every Xbox 360 game that used Xbox Live for matchmaking was required to use skill based matchmaking. They had two categories of matchmaking "Ranked", which heavily favored matching players based on skill (with a tradeoff of potentially longer matchmaking time, not connection quality) and everything else, which still used player skill to find the "best" matches but it would loosen the skill requirement if it was going to take too long to find match.
I have no doubt that Destiny uses, at least to some degree, skill in it's matchmaking criteria and likely always has. Since Halo 2 and especially Halo 3 Microsoft (and presumably Bungie as a part of that) has talked about some amount of filtering players at the same skill level into matches together as a way of pushing online "stickiness". And online stickiness is a major market desire for the gaming industry because the longer you keep your game and play it online, the longer it stays out of the used game bin, which means more people buying new copies.