Sooooo you say your on the fence about the 15
Welllllll almost everyone says things like "The 15 is the best steak knife you will ever own" and "Its great in the kitchen"
What doesn't get said enough is "Its a Becker!" you can beat it like a red headed step child and it will grin at you stupidly, and ask for more.
YES it is slimmer and thinner. YES it is great for food prep.
However knives of almost identical design were used for EVERYTHING by men who needed their knife to survive, in a era when you couldn't say "welp, I'm dont camping time to head to McDonald's...." Because everyone was camping, by today's standards...lol
The 15 will do anything you need a knife for, including battoning, of appropriate sized sticks.
Obviously its not for chopping down trees, but dont write it off as a kitchen knife. Get one and use the hell out of it, because its a great knife.
I wouldn't call it a survival knife, because that name implies that the knife is massively overbuilt and can be abused beyond common sense.
I would however say that you can survive quite nicely with a 15, especially when you consider that it IS thicker stock than the french trade knives that I believe were the heart of its inspiration.
I LOVE my 15 and just because I wanted its soul to show I tricked one out.
Still think its just a kitchen knife?