Based on what HA said I think he has switched DRM on.
Personally, I don't think DRM has ever helped any small time developer to shift more units. It does help large-scale products for a very narrow time window, but otherwise you will find DRMfreed copies of almost anything from large to tiny productions on the high seas (games, any kind of software, but most of us know that). I get why developers, even small scale ones, instinctively want to protect whats theirs, a very human reaction, but DRM has, with few exceptions*, the same effect as security theater. Its not effective, but people buying into it do it more based on belief than hard facts. It gives them a sense of control over pirating, though it doesn't really stop anyone pirating.
DRM will not help shift more units. It will annoy people who might have been legitimately bought in on steam. Even people who already bought it on the website in the past. Steam is about convenience. DRM weakens that convenience, and in the case of a niche tool, which GridCartographer is, it will limit the convenience even further. DRM doesn't stop pirates, but it does stop people from becoming customers.
*When is DRM ever effective? When you have such a large demand for a product and your customer base is so big that people want it the moment it gets published, salivating over every detail before it even comes out and then have to decide whether to get it for free or pay 60$, and will do if they can't find a pirate copy. Basically when you have a ridiculous amount of customers with low impulse control.
