Yes, because it will give you improvement. But, set the cost and return in context with other potential investments. This is a very handy chart to help give you some rough order of magnitude guidelines.
The "Aero Frame" at the bottom are both considered TT frames, but the tubing design is different. You are on an aero road frame, which is something different. Road frame geometries are different from TT frame geometries, so your final optimized position on your Kestrel may not be as good as it could be on a true TT frame, so you have that intangible to consider in addition to just the pure aero advantage of a true TT frame.
If you found a good value on a used frame and did the conversion yourself, then in my opinion, it is worth it. I would do this before spending too much effort buying parts to optimize position on the Talon, because the expenditures could be throw-away.
But big picture: If you are just getting into tri, and you have nothing, then I would get a good tri suit and aero helmet first. Then wheels or frame upgrade would be my toss-up for second. Mainly because you likely be buying a combo of aero bars, stem, and TT saddle along with the frame for a net massive gain over your current setup.