Might be cool in the US but I don't see the point of a more versatile AR in Canada.
Also, a person wanting to pack up his AR in a smaller package could just pull the upper off the lower. Might not be quite as small but I don't know about you but my truck has more than enough space to put a case big enough for an 18 inch barreled AR.
Looks like a nice rifle though and I like the idea of being able to convert it to 300 Blackout without having to buy another upper receiver. Although the cost of adding a gas system to the exchange barrel may end up equaling the cost of an upper.
I love AR's but I don't see this making me want to sell my rifles to buy it and a couple different barrels.