I don't think the difference is due to snobbery either.
Apart from its structure, which Simone has explained, Tarot can be used as a form of oracle but also for other things that are specifically linked to its structure - games, Tree of Life meditations, Progression of the Soul meditations, Numerological correspondences (either psychological or predictive) are some of them. Divination with tarot can be as simple or as complex as you choose, because of its esoteric nature and its structure, which incorporates all sorts of levels and elements.
The Major Arcana of the Tarot also represent a series of 22 archetypes that are arranged sequentially according to a logical philosophical or esoteric progression. As a product of the Renaissance, these archetypes and their progression derive from the Christian-inspired neoplatonism that was popular at the time. But they have proved wider than their origin - and can be thought of as universal archetypes arranged in a universal progression of the soul - or indeed, a Hero's Journey.
Oracle decks are often more free-form, with no set structure, though their creators may well devise a structure for them. You tend to read them in a more intuitive, free-associative way. A lot of so-called oracle decks are not really divination tools, but more tools for meditation, self-help, magic or psychological exploration. Or even for cheering yourself up on a rainy day, which is a lovely gift!
As Simone said - it's perfectly possible to read tarot purely intuitively, like an oracle deck, but that's only one way of reading it. Many readers use a mix of intuition and system (numerological, kabbalistic, you name it) that suits them. Despite the intuitive readings, there are meanings that are commonly accepted for tarot cards, which is not the case, of course, for oracle cards, since they are one-off creations.
One more thing - there are many other oracles that are, like tarot, organised systematically and which have stood the test of time: runes and i-ching are among those.