You know I can kind of see the sense in getting a Denali for a first tri like this guy did. If you have a decent hybrid or rigid framed MTB it's probably more sensible just to get some narrow/slick tires. However, if you don't have a bike at all or your current bike is a Magna or something like that, well, there are worse options.

I'm not delusional in that it's a great bike for a triathlons or anything but I can see somebody doing one tri just to do it, then either they want to do more, or they're done. If they want to do more, they can then get a better bike. If they're done, they haven't invested much. The Denali only has to last for few months of training maybe and the race itself. Long term reliability and durability isn't really an issue.

Yes, an older used road bike in good shape is a better investment (IMO) but like has been said plenty of times, buying used is a great option for some, - not so good for others.