The lack of examples on the Stock market is made purely by practicality. In the past I have developed and used strategies on Stocks, but as you can imagine, there were problems of correlation between the various stocks and it was not possible to create a diversification as it should be. By operating on futures, stock indexes can be combined with currencies and commodities in order to achieve a completely different exposure.
However, developing strategies on stocks is 100% similar to the other instruments, only the amount to be traded changes (I generally developed assuming fixed trades of 10,000 euros).
Furthermore, there is much more leverage using forex and futures, not in the sense that we lose or gain more, but in the sense that we can be more flexible.
I'll explain.
The margin for a DAX is about €10,000 (in intraday and slightly more than twice in overnight) and the gain is €25 / point INDEPENDENTLY FROM THE DAX VALUE AT THAT MOMENT.
Apple today is worth a value, tomorrow another, I always gain 1 $ / point but the margin is equal to the value of the stock (or maybe 1/2) but it keeps on changing.
If we refer to the margin level, then I can use multiple strategies with the same risk capital.
Then there are dividends that futures do not have.
As of transaction fees and bid / ask spreads thery are almost the same, give or take, perhaps the shares cost a little more, even if this varies from broker to broker and from market to market.