Unfortunately they lose their practicality when put in an arbitrary list like this. Here's why:
1. No founder has the time to execute on all 10 of these tips. And if they do, then each of the 10 tactics will only get a half-hearted attempt and yield few results.
2. Perhaps they recognize they can't split their attention on all 10 things--plus the 10 things from another article, and the 7 things from another, ...--so they decide to focus on just 3. Now the problem: Which 3 do they choose? The tips vary in their practicality, so choosing the wrong 3 can result in a big waste of time and money.
For example:
> Customize your site with geo-specific elements.
Maybe it will result in "double-digit conversion lift," and maybe (most likely) it won't... But the same can be said for the 1,000 other conversion optimization tips.
There are too many better uses of time for an early stage startup--some of which you mention, such as experimenting with channels and measuring costs per acquisition--to be tweaking a word here and a button color there.
3. Two prescriptive paragraphs on a subject as broad as "paid advertising" can do more harm than good. I've seen too many companies flushing money down the drain on AdWords without even realizing it. In one case, a company meant to advertise to python developers but instead was using up their entire budget on clicks from people searching for snakes.
4. Some of this is easier to say in retrospect than actually do in the present. For example:
> Define value proposition early.
Startups lack a good value prop not because they didn't think to do it sooner, but because it takes time to figure out what exactly is that value prop. As you said yourself, it takes many iterations and many conversations with users before you can reach the "a-ha" moment and figure out the magical sentence.
---
All this to say: You obviously have great experience and a desire to share your knowledge, but you're doing yourself (and others) a disservice by diluting that knowledge into clickbait listicles.