lol. I didn't see anyone in this forum advocate to talk to the echo outside of the home to unlock it. If you are outside and want it unlocked, just unlock the way you always do without the echo involved. There are several scenarios where someone would want to unlock the house, but I will just mention three.
1) The front door is no where near where my family hangs out so when friends and family come over, it is nice to say "Alexa, unlock front door 1234" so my friends can come and join us in the theater room, but I cant say that - I have to say "Alexa, turn on front door" via virtual switch, PLEG, and a scene. Could I just do this with Vera and my phone? yes, but then we could do that with everything that Vera already does and makes all echo/vera related discussions pointless. Might as well just get rid of the echo/vera integration and go back to 2010.
2) I have schlage lock on the doggy door in the garage. I want the echo to let the dog out so I say "Alexa, turn on doggy door", but it would be nice to say "Alexa, unlock doggy door" without a bunch of hacks or even entering a pin number for this specific case. Once again, not insecure because the doggy door never had a traditional lock on it anyways. Its actually MORE secure now.
3) The family is running around on the property going in and outside of the house doing all sorts of activities and it would be nice to tell Alexa to go into a mode that unlocks all doors around the house. I have this working right now with a scene called "relax", but once again with a bunch of hacks.
It never crossed my mind to unlock the house with the echo outside of the house