On the surface, it’s not bad. If, for example, you move from one state to another, your previous state may not know you don’t live there anymore. So if they see you haven’t voted in that state for a while, they’ll assume you don’t live there and remove your name from their registration.
The problem is, as usual, how it gives conservatives in the US cover to remove legitimate voters. If you haven’t moved but also haven’t voted for the last several election cycles, you might get removed even if you intend to vote in this election. And you can see how that’s a short jump to “Oh no, we accidentally removed a whole bunch of people who were going to vote against us and darn it, wouldn’t you know there’s no way to fix this in time!”