Smart(ish)-watch+wireless earphones is the optimal solution for me. Having a Pebble Time Round allows me to communicate with people while I'm doing something (I text way more than I talk, and Pebble's/Android Wear's voice-to-text isn't bad), and it generally makes using my phone as a phone easier since I basically skip a step.
I must say, at this juncture, that the Pebble grants this ease-of-use with the Galaxy S5 Active generally not being a pain-in-the-ass to use as a phone/communication device and light+small enough to fit into the pockets of my somewhat-close-fitting pants. The Pyra will never go into my pockets and will live in a bag when I'm out and about, which is not an issue since I carry a bag everywhere I go. However, having to pull the Pyra out of a bag whenever it rings or pings is a major pain-in-the-ass. Inconvenient tools are unused tools.
The Pebble eliminated a step with the GS5A It will eliminate 2 steps with the Pyra. Pebble+BT earphones will kill 3 steps. As for Fitbit killing Pebble, you can find the OG models second-hand for hella cheap, and finding them isn't an issue.
As for the 2nd handheld device, I'm not so sure about that. It enables communication on-the-go without drawing the Pyra out and it's more pocketable, sure. If you're replacing a phone, then why would you essentially add it back to your carry? Yeah, watch+buds turn 1 device into 3, but they're almost weightless and much easier to carry, not to mention the freed-up pocket space as a result. OG Pebbles last a week on a charge, and the earphones can charge from the Pyra for a few mins if low on juice.