For the artwork.
The stories are a little -- dated, in places. Simplistic. Sometimes embarrassingly propagandistic. Such as one of the "Crime Drama" pieces, titled "Trapping New England's Chain Murderer!" This story of a serial killer of women published in May 1947 has some truly riveting and visceral artwork. However, it's in the service of a laughable message about the dangers of falling victim to the marijuana. Check out the last page:
"I killed 'em all!! When I don't get a reefer, I go crazy.... crazy!"
That was the government's line. Reefer makes you into a crazed, well, chain murderer.
It's interesting that the comics toed this line about the dangers of the marijuana (and Simon and Kirby's story was not exactly the only comic warning about the dangers of reefer), yet that wasn't enough to prevent the government going after them. As Mark Evanier notes in the introduction to the "Crime Drama" section,
The Kefauver Commission -- helmed by Tennessee Senator Estes Kefauver, who hoped to ride it all the way to the White House -- saw the gunplay and saw the blood, and that was enough for them, especially since the entire industry was suspect.
From out of that senate committee investigating comic books (!) came the comics code, which did a pretty effective job of neutering comics content up into the early 80s.
Of course, comics today are propaganda-free, as artists exercise their expanded freedom of expression to write stories that challenge authority and the status-quo.