The free version of Resolve is still limited for more serious / professional applications; e.g. not making use of hardware acceleration, not having certain effects, and not processing certain professional workflow codecs.
With this strategy, Resolve is essentially the "go-to" for newbies into video editing.
What's so great about Resolve licensing is their lifetime license. Pay $295 once, get it forever. For commercial productions, Blackmagic gets their $$$$$ from their cameras, physical control panels and hardware, etc. These, again range from good value (for entry and mid level) to expensive.
Within 2 minutes, I was running into features i needed to pay for. Within 20 minutes I had bought a home copy because of how integral it is to my workflow.
They get people in by being able to do the basics, but anything remotely complex, you pay for.
They get people in the door with a really powerful free editing software, and once you've invested time into learning it and made it part of your workflow, you want to pay the £300 to upgrade because it's too much hassle to learn a new editor, and Resolve is awesome, but you reallly don't want to keep waiting 3hrs to generate 1/8th res optimized media for your whole project before you can preview at more than 10fps on an i7 Extreme Edition (that's how they got me, if you couldn't tell).
It's an effective free -> paid product-led conversion path to acquire customers. Being on HN and presumably working in tech/SaaS, this is a familiar and effective business strategy.