Steel type only matters in that you can't make a great knife out of a tin can. Jon sells it, therefore the steel performs.
or when just the info about the steel doesnt really speak to the particular qualities of a steel/heat treat combo. This is why i try to talk to people about the qualitative properties of these knives more than just steel type and hrc. When people become too obsessed with just steel type and hrc, it gets in the way of understanding what the knife is all about.
Devin's made a great point here... consider this. No one really talked about aeb-l before larrin and devin started on it. All of the sudden, everyone and their mother is using aeb-l saying how its such a great steel, and the ht is always great. The truth is that aeb-l is not such a special steel. Its a relatively simple, not crazy high carbon steel that can take on a wide variety of properties depending on how it is forged, ht, and ground. What devin does is different from others, but because he does a great job, aeb-l now has quite a few fans. I've tried quite a few recent aeb-l knives... some just flat out suck, while others are ok, and even fewer are good (there are even fewer that i think are great). Just knowing a knife is aeb-l will not help you understand more about the knife. Using the knife and seeing how it sharpens, holds up, the kind of edge it takes, etc., will tell you more than almost anything else you can do.
I dont always share steel types because i'd rather have a discussion about how a particular line sharpens, holds up, responds to certain tasks, etc. Its also my excuse to make sure i've used as many different things as possible (and all of the things we sell).
The heat treatment of any steel can affect the way a steel or knife performs. A heat treatment should be geared to the type of knife that is made or manufactured. The steel grade is only the beginning. Wasn't trying to offend anyone.
Usually it's secret when the steel type is considered to be mediocre or not cool ATM like AUS-8 type. AUS-8 is considered to be a mediocre stainless steel by knife enthusiasts/nuts and if you google it, you will find ppl recommending other alternatives.
I can understand that this information can scare the customer and he will miss on a great knife and the vendor on a sale.
Having this in consideration, it does not matter a lot if you buy from respectable vendor, like Jon for example and you ask all the right questions. In case I buy from an unknown/shady vendor this is something I would like to know. And most likely I will let the opportunity pass if such info is not available.
P.S. Note, I said usually in the beginning. That means often but not all the time