Republic’s reasonably up front in the FAQ in the Original post. This is an experimental product. The current iteration isn’t necessarily the final one. We’ll see. For now, it is what it is and I’m happy they’ve introduced it. I’m not a believer in making the perfect the enemy of good. A product or service may not perfectly meet my wants or needs but may still be good.
I’m really not certain what you’re asking for. Republic swaps GSM for CDMA SIMs and vice versa to address coverage issues when appropriate and does not charge for doing so. In fact, it’s relatively easy to swap back and forth manually in the same phone. I don’t see it as something a typical user would want to do but is possible. If you’re talking about Google Fi like on the fly switching using the same SIM, that’s another matter.