If you've recently browsed for kids' educational Apps, what is going on? Some only work if you already have an account. Some are full of cartoon characters, progress bars, and collectables. Some seem to be only charts and tables showing progress. The actual activity, when you can find it, looks like flash cards. What is going in? There are two things: some are for the a school market; and there's a theory that education Apps need to feel like games.
Education Apps for school aren't used in the classroom. They're assigned as extra homework, in a parallel system. They often have several grades worth of exercises, over several subjects. They're selected at the school or district level. At that level, evaluating the exercises isn't practical. The main thing these Apps need is reliability. An entire class needs to easily be enrolled and given passwords, and teachers need to be able to quickly check progress for midterms. That's where all of those charts matter.
When you see these Apps for individual download, it's already been assigned and your kid was given a password at school. It doesn't need to sell itself to you -- it's already been sold.
The other idea is that education Apps are competing with games. There's no special reason this would be true, but it's caught on. In theory, your kid has an addictive game on their device, right next to the education App. They don't enjoy learning and you don't monitor their device time very well. The only way they'll open the education App is if it out-games the game.
One trick is having an avatar, like a talking dog that pops up everywhere. Another is being able to repeat exercises to get coins. The coins are used to buy "collectables". These might be different clothing (and hats, glasses, shoes) for the avatar, or pets to stand next to them. There may be an area where you can buy and arrange furniture. It's also important to give lots of praise, like fireworks after each completed exercise. Part of praise is showing progress. Maybe a thermometer which animates filling a little each time with spurts of mercury, or a ring with 6 segments which light up.
Doing that is surprisingly easy. A kid's game typically has a home base, a map with unlockable areas, and short levels which are repeated to collect loot. Often the levels aren't all that much fun, at least not the 4th time, but you need the gold coins. An education App can use all of that, using the education exercises as the levels.
Neither of these are what we expected. They're just what we have. They're made by regular people doing their best to sell us what we seem to want.