Using Blocks vs Template Edit
Technically putting things straight into a template may have better performance.

However if you create a static block and make sure it is cachable on the whole site the difference will be negligible. There are many other ways to improve performance and this is right a the bottom of the pile. 

There are many other things that you can do to improve performance. Taking the view of the site as a whole. The flexibility that a block gives you may give you may outweigh the performance gains you achieve.