Some ways of going about things are more verbose, but the difference in performance isn't negligible. There will always be a balance between verbosity and performance.
Granted this page specifically pertains to jQuery, but most libraries expose ways for developers to start going down the long road of performance tuning.
As the original author of those 7 performance tips, I suggest you ignore them. :)
Spending 10 minutes with the DevTools timeline (or network waterfall) will give you way better insight on your perf issues than following these microptimizations.
This has lots of information on jQuery and performance choices:
http://learn.jquery.com/performance/
Some ways of going about things are more verbose, but the difference in performance isn't negligible. There will always be a balance between verbosity and performance.
Granted this page specifically pertains to jQuery, but most libraries expose ways for developers to start going down the long road of performance tuning.