Live Aid was way more influential and useful for their career. Don't forget, it only reached number 28 in the US on release. Live Aid, on the other hand, caused great swathes of the globe to buy their records.
Actually the largest percentage surge in U2 concert attendance occurred going from the War Tour to the Unforgettable Fire Tour. Larger than going from the Unforgettable Fire Tour to the Joshua Tree Tour.
Take the city of Philadelphia for example:
War tour: 6,000 tickets sold
Unforgettable Fire Tour: 40,000 tickets sold
Joshua Tree Tour: 104,000 tickets sold.
The increase was more than six fold going from War Tour to the Unforgettable Fire Tour. Going from the Unforgettable Fire Tour to the Joshua Tree Tour was less than a three fold increase.
So what factor so dramatically caused this increase between War and UF tours? Most believe it was the Under A Blood Red Sky Album and Video. This was widely available to the public, played on radio, and played on MTV throughout 1984.
In contrast, Live AID was a one time broadcast, that was not shown in its entirety again until 1995. No album, single or video of the performance that could be purchased at the time either.
The Under A Blood Red Sky album went on to sell over 3 million copies in the United States alone. At the time, these were the most widely heard live performances of U2 for the general public.