A public billboard vs Google Ads
These are not competitors so much as different instruments. One buys intent at the moment somebody searches. The other buys a fixed, visible position that everyone sees in the same order. Knowing which problem you have decides which one to use.
What keyword advertising does well
If somebody types "invoice software for freelancers" into a search box, they have told you exactly what they want. Nothing beats being there for that. Search ads scale, they target, and they measure conversions properly. For a product with clear existing demand, this is the default and should stay the default.
Where it gets painful
The cost per click in competitive categories has climbed past what most small products can carry. Financial, legal and health keywords are expensive before you account for the policy review that can pull a campaign without much explanation. And the moment you stop paying, you disappear completely, there is no residue.
What a public board does instead
It buys a position, not an auction slot. One flat payment, no daily budget, no bidding strategy to tune. The position holds until somebody outbids it, which means a spot bought once can keep working for weeks. It is also legible in a way an ad is not: the price is public, so the placement reads as a deliberate move rather than a sponsored unit people have learned to skip.
The honest limitations
There is no targeting. You cannot pick who sees it, you cannot run creative tests, and the volume is a fraction of a search campaign. You can be outbid at any moment with no notice. And the links are nofollow, so there is no SEO benefit, this is attention, not authority.
The short version
Use search ads for capturing demand that already exists. Use a public board when you want a visible position, a price you can see, and a placement that does not vanish the day the budget runs out. Most products that do well here are launching something and want to be seen by builders, not converting a warm search query.