I used ONLY tarot for 10 years.
But last year I was drawn to an oracle deck and bam! Now I love oracles too lol.
The difference, might depend on who you ask… But the biggest difference is probably the lack of a ”system” in oracle decks. Tarot is always 78 cards, major arcana, minor arcana, court cards, aces… You don’t ”have to” learn how the courts are different from the minors etc when using an oracle deck. Some of them have their own system though, and come with meaty guidebooks.
But I know a lot of people ignore the guidebooks with oracles, they’re kind of more intuitive. You look at the cards and let your intuition guide you.
For me personally oracle decks feel more spiritually oriented (well, at least the ones I have). I don’t often ask ”practical” questions, and I love doing daily draws with oracles asking what I should focus on that day. Tarot can have a more practical use also. I sometimes feel like oracles can be too fluffy, too affirmative and positive, but I try to find decks that also include darker cards… If I really need an honest, straight-forward, answer I usually go for tarot.