We can split hairs about which early computing devices first implemented which automatic computing ideas, but I hope I can make 2 statements without much controversy.
The ENIAC was the first device to be automatic, electronic, general-purpose, and digital. That combination contained synergies that were more than just the sum of the features.
In particular, the ENIAC advanced the state-of-the-art in computing speed by 3 orders of magnitude, from 5 or 6 additions per second to 5000 additions per second.
I gave a talk in 2012 about early computer history, and a substantial portion was dedicated to the ENIAC.