As someone whose inbox has been on the receiving end of some funding announcements recently, this crunchbase method is definitely used more outside of job searching: recruiters, sales folks, etc, all love to jump on a funding announcement.
Wish more engineers, designers and product people used this approach - nothing better than an inbound candidate who gives a shit and can growth hack.
It lets you present your value, show you can communicate well and that you really want to work there.
If you just drop a generic cover letter, that's low-effort. If you spend the 10 - 15 minutes to write a good, succinct message on how you think you can help and that you are interested in the company, that's huge in my opinion.
I think I have done it in total about 5 times and gotten hired twice from it which isn't a bad success rate!
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With all of that said, there is a certain size where this strategy stops being viable but I am not sure where.
As a company gets bigger, it would definitely become less likely to work in my opinion but inversely, I think the smaller they are, the better it will work.