The Delta SkyMiles American Express credit cards contain some excellent perks for loyal Delta fliers — and living in the Delta hub of Minneapolis-St. Paul, that's a lot of us. But the cards' reward-earning rates just haven't been that impressive compared with other premium travel credit cards out there, even some no-annual-fee cash-back cards.

Now, with a host of new benefits announced Monday, the Delta-Amex SkyMiles cards are more competitive, and one just could become your primary plastic.

The changes, which take effect on Jan. 30, are spelled out at NewDeltaAmex.com. To celebrate, Delta has rolled out expanded welcome bonuses in October of up to 75,000 miles.

The mid-level Delta SkyMiles Gold card will become a much stronger card if much of your spending is on dining and groceries. The SkyMiles you earn on those purchases will double from 1 per dollar spent to 2. You'll still get 2 miles per dollar on Delta purchases.

The gold card's annual fee will rise from $95 to $99. But now if you spend $10,000 a year on the gold card, you'll get a $100 Delta flight credit, effectively canceling out the annual fee.

The Delta SkyMiles Platinum Amex takes it further for frequent travelers. Rewards at restaurants and supermarkets will double to 2 miles per dollar, while Delta purchases will jump from 2 to 3 miles per dollar. Your rewards for hotel spending will triple, from 1 to 3 miles per dollar.

Delta also threw in a juicy $100 credit toward Global Entry membership every four years, or $85 for TSA PreCheck every 4½ years.

Unfortunately, the platinum card's annual fee leaps from $195 to $250. By my math, if you charge around $400 a month on dining, groceries, hotels and Delta, the expanded rewards should cover the fee difference.

Both cards retain their best existing perks: priority boarding and free checked bags — which can quickly cover the annual fees. With the platinum card, you'll still receive a free domestic companion certificate once a year.

Simon Peter Groebner is the editor for Midwest Traveler. Follow him on Instagram at @simonpeter6.