I can transfer funds from my Finnish bank account to my German bank account and I get a push notification from the German one within seconds of submitting it. If your SEPA transfers aren't instant, it just means that one or both of the banks involved haven't just adapted it yet.

Banks might also have only implemented receiver or sending, but not both. My mom can receive my instant SEPA transfers, but she can't send me one back since her bank has only implemented the receiving part.