Quick, pull up VictoriaMetrics.com and Honeycomb.io. Tell me how the design differentiates the brands. Sell me on the idea that anybody picks one over the other based on these web designs.
The “vibe” of a product is absolutely important. Do logstash and datadog have similar vibes in their log viewers? Fuck no. I can instantly tell I’m using something related to that tool because of its design language. That helps it stay sticky. If you’re datadog, you don’t want users thinking the product feels and looks exactly like all the other log viewers. You want them to think it’s unique and the best or whatever. Marketing sites extend that, and are absolutely a component of the “vibes” you get from a product before doing a strict engineering breakdown.
Yes they both have the same overall structure as the Stripe landing page but if you can't tell the difference between the level of execution of those three, then you're just arguing for mediocrity.