Why "vs computer" got harder to find
Online multiplayer is worth more to an app than a local AI opponent, and not because it's a better game. Matchmaking requires an account, which the app can use for retention, notifications and marketing. It also keeps you waiting and coming back, where a computer opponent lets you play one round and close the app — fine for you, worse for engagement metrics. So the free, ad-supported version of Checkers you find is disproportionately likely to be the multiplayer one, even when a simple AI would serve most casual players better.
Where a computer opponent does exist, it's often either too easy to be interesting or unbeatable in a way that feels less like skill and more like the app just knowing your moves in advance. Genuine difficulty levels, where the computer looks further ahead as you go up, are less common than the label suggests.