when do i need to cache templates?

[Dr.CustUmz]

im editing my new release
https://vborg.vbsupport.ru/showthread.php?t=322031

and in it i cache a temple, then in the next plugin i eval that template so i can shortcode it into another template, like so:

<plugin active="1">
      <title>cache templates</title>
      <hookname>cache_templates</hookname>
      <phpcode><![CDATA[

        $globaltemplates = array_merge($globaltemplates, array('drc_lf_css'));

]]></phpcode>
    </plugin>
    <plugin active="1" executionorder="5">
      <title>global templates</title>
      <hookname>global_start</hookname>
      <phpcode><![CDATA[

eval('$drcextcss  = "' . fetch_template('drc_lf_css') . '";');

    ]]></phpcode>
    </plugin>

in the mist of adding a new template to global cache i accidentally removed the original cache, which had no effect on my product.

so im just wondering. when is there the need to cache a template? I always thought they needed to be cached