A little subjective, but here's my take:
Go City Cards and similar passes have popped up all over, especially in popular US and European destinations. They've become a sort of staple client query for some spots, especially London and Paris.
My recommendation for London and Paris is typically against for most travelers. The cards are great value if you can get to 2-3 or more galleries & museums each day you use the pass.
That's a great deal, but a little difficult to actually achieve because you're probably going to want to spend more time enjoying these spots and my clients who were insistent on purchasing the passes almost always come back saying they were tired, stressed, or just disappointed that they didn't get their money's worth.
It's hard to pack in 3 world-class museums a day and have a good trip haha
Miami, on the other hand, has a more activity-focused set of attractions included in the passes. With actual walking tours or activities you'd enjoy because of their participation.
For example, you might try hopping on and off the Big Bus tour bus and then taking a bike rental in South Beach; bike around a bit or even cycle up to North Beach for some cool sights in the Faena District (you can't bike on the boardwalk there, mind you). Heading back south, grab a dulce de leche milkshake at Hagen Daaz on the way back down Collins Ave, stopping in the pedestrian area of Lincoln Road.
Then return the bikes, head over to the ARTECHOUSE for a futuristic session of art-meets-tech and then catch the 6:30pm Art Deco Walking Tour or the Big Bus Night Tour.
Maybe instead you just want to chill out on the boat floating by Millioniare's Row or cycle hard with Cycle Party in Wynwood? You've got several choices for airboat rides in the Everglades to go look for 'gators too.
Day two? Jump on the group bus tour to Key West and don't worry about driving back, so you can have a responsible few drinks (*I'm winking here*) on world-famous Duval Street.
If you've got kids, Miami Seaquarium, kayaking at Coral Gables, Zoo Miami, Lion Country Safari...
At the time of writing, it's all included in the pass - except milkshakes on Lincoln Road or drinks on Duval Street. You're on your own for food & drink or souvenirs.
Your passes are good for however many days you select, 2, 3, or 5 of any calendar days during a consecutive 14-day period. They even include spots in Orlando, Daytona, and the Keys if you're on a road trip!
Here are some great rates from our partners at Luxury Tours Miami (US$)