I'm feeling like airing my thoughts on crates and why people open them, so here I go

I see opening crates as a matter of currency conversion. Real world currency can be converted into TF2 currency by buying keys through the store. TF2 currency can be coverted into real world currency by selling unusuals (mainly). For most players, the only way to get an unusual (and as such recoup some of the time/money put into the game) is through uncrating. Uncrating stranges is something of a stopgap measure, encouraging people to keep uncrating and maintaining the ingame price of keys, since a player must be willing commit the full cost of a key before uncrating, but they get some of their cost back in stranges.