Joomla meta description is required because it forms a more compelling web page in search engines. More people will click on sites having a proper meta description in the search engine snippet than random descriptions. But if you wish you can remove the Joomla meta description completely. Edit the templates/mytemplate/ component.php /index.php file.
<jdoc:include type="head" />
foreach ($document[scripts] as $key=>$value){
if (stristr($key,$baseURL)==NULL){$url= $baseURL."/".$key ;}else{$url=$key;}
$scripts .= "<script type=".$value." src=".$url."></script>"; };
foreach ($document[styleSheets] as $key=>$value){
if (stristr($key,$baseURL)==NULL){$url= $baseURL."/".$key ;}else{$url=$key;}
$style .= "<link rel='stylesheet' type=".$value[mime]." href=".$url." />"; };
foreach ($document[script] as $key=>$value){
$scripts .= "<script type=".$key." >".$value."</script>"; }
foreach ($document[custom] as $value){
$custom .= $value; }