Tradition, most of the time, gives rise to that feeling of "familiarity," but it need not always do so--sometimes "traditions" sprout out of misremembering or a sudden change that "just seemed natural."
Consider, for example, the trope of giving Barbarians and Fighters fewer skills than other classes. It never existed prior to 3rd edition. In fact, as I recall, it was even common for them to have
more skill-equivalents (e.g. NWPs) than other classes, because the origins for these classes were Conan (who had tons of different skills) and various main characters spread across fiction (e.g. John Carter of Mars) who needed to survive by a mixture of thews
and thinking. Yet as soon as 3e put the reduced-skill-point Fighter and Barbarian (the latter being
illiterate unless you paid extra skill points!), it became instant tradition--several successor games,
including 4e, preserved some of that BS, and even 13th Age, a game designed by 4e's lead designer, almost included it too, but changed their minds due to playtest feedback that vehemently said
no.
Tradition has honest, legitimate value; I don't mean to paint it as something pointless. But I often find that people portray it as inherently better than trying to investigate
why things are done the way they are done, and what ways might achieve the same ends but more effectively. For primarily aesthetic things, it makes no difference, there's nothing really to
test, so those should generally do whatever the creator things is best--the value of tradition there becomes the evoked feelings, as is the case with all aesthetic things. But for mechanics, it's a different story.
I mean, consider the following comment from above:
If there isn't a very good reason for it to change, I want it to remain the same or very similar.
In other words, tradition is valuable
in and of itself, and you need not just good reason, but a
very good reason (emphasis added) for it. And that leads to a big problem: A lot of people are very unwilling to even
consider changes to traditions they currently like, even if those changes would actually be
useful to them.