That's also my understanding. Heroku, on the other hand, has no time-limit on their free tier, but it's always kinda broken (startup times). AWS's free tier is the real deal. That's a trade-off.
But that's orthogonal to the point I was making, and the comment I was replying to. If someone likes Heroku because of it's pricing clarity and its ease of setup... well, the pricing simplicity of an EC2 instance is just as good, and the ease of setup is even better.
More broadly, if you're evaluating them against each other....
Heroku isn't the easiest to set up, nor is it the simplest. It's not the easiest because you have to learn a bunch of Heroku-specific things, that you'll just have to reinvent/relearn/etc if you ever want to switch providers. To call it "vendor lock-in" might be a bit of a stretch, but it has aspects of that. With EC2, it's just server management, same as it ever was, same as it'd be on some other cloud.
(Note that many OTHER AWS services are far worse than Heroku in this respect. And/or better, depending on your goals.)
Heroku aims to be a sweet spot. A few hours (or days, maybe) invested in learning to use it properly, and you get a pretty reasonable bundle of tools and support and so on. But if you want to dive deep, Heroku's probably a waste of time. And and the other extreme, if you don't want to learn anything about an individual provider's proprietary crap, then Heroku also will not work out that well for you. Saying "this is our sweet spot" is a respectable position, even if you don't like the sweet spot.
(Personally, I'm still boycotting Heroku over their years of misrepresenting their "dynamic mesh routing", which was always fiction and which they lied about for years, and charged customers for something that they knew full well they weren't delivering. Don't get into bed with sociopaths, even if you like their sweet spot.)