For these industry-disruptor things you need some degree of support from the industry you're disrupting (i.e. you need to sell to utility companies that have strong business relationships with the large generation technology providers in the space). In practice this means raising money from, or partnering with, the right people that can leverage industry connections.
It is easier to get the right investors and partners if you are not controlled by Alphabet, because investors and partners have more assurances of the governance leverage they get for their money/effort. If you are Sergey's pet project, you are very vulnerable to mood swings on his (or Google's) behalf.
It makes a lot of sense -- it's possible that this ends up being a very viable, scaled business with low margins. If the margins are lower than Alphabet enjoys as a whole, and if there isn't an argument for synergies with existing Alphabet businesses, it could simultaneously be a very good opportunity but also not accretive for Alphabet share holders. Part of the restructuring of Alphabet/Google and the hiring of Ruth Porat was to be more disciplined about not doing everything possible with shareholder money. $24M here, $24M there, sooner or later you're talking about real money.
It’s a good way to verify that your moonshot project is viable, and not just a hobby of somebody who, some time ago, managed to convince management an idea is worth working on.
The big thing is strategic partnership and support from industry. If you look at who’s invested into Malta from the companies they list in the article, everyone one of them is highly relevant to some part of the business model / supply chain of Malta, with each company generally being at the top of their respective industries.
I would question the confidence if a super big company starts something and is like: uh you know. We collect money from someone else.