REST API return encoded Multiline Textfield but show it correctly

I save a JSON string in my SharePoint list. This looks like:

{"columns":[{"name":"A","visible":true,"width":200,"sort":{},"filters":[{}],"pinned":"left"},{"name":"B","visible":false,"width":150,"sort":{},"filters":[{}],"pinned":""},{"name":"C","visible":true,"width":200,"sort":{},"filters":[{}],"pinned":""},{"name":"D","visible":true,"width":200,"sort":{},"filters":[{}],"pinned":""}],"scrollFocus":{},"selection":[],"grouping":{},"treeView":{}} 

But if I request it from the SharePoint I get:

{   "d": {     "results": [       {         "__metadata": {           "id": "Web/Lists(guid'78e7e9bc-d85f-4c18-8aeb-213a68b28154')/Items(1)",           "uri": "http://sharepoint2013/sites/acme/demo/_api/Web/Lists(guid'78e7e9bc-d85f-4c18-8aeb-213a68b28154')/Items(1)",           "etag": "\"1\"",           "type": "SP.Data.SettingsListItem"         },         "Configuration": "<div class=\"ExternalClass41AB4CF73C1C4DCB82C4F0B8CCCBC7AE\">&#123;&quot;columns&quot;&#58;[&#123;&quot;name&quot;&#58;&quot;A&quot;,&quot;visible&quot;&#58;true,&quot;width&quot;&#58;200,&quot;sort&quot;&#58;&#123;&#125;,&quot;filters&quot;&#58;[&#123;&#125;],&quot;pinned&quot;&#58;&quot;left&quot;&#125;,&#123;&quot;name&quot;&#58;&quot;B&quot;,&quot;visible&quot;&#58;false,&quot;width&quot;&#58;150,&quot;sort&quot;&#58;&#123;&#125;,&quot;filters&quot;&#58;[&#123;&#125;],&quot;pinned&quot;&#58;&quot;&quot;&#125;,&#123;&quot;name&quot;&#58;&quot;C&quot;,&quot;visible&quot;&#58;true,&quot;width&quot;&#58;200,&quot;sort&quot;&#58;&#123;&#125;,&quot;filters&quot;&#58;[&#123;&#125;],&quot;pinned&quot;&#58;&quot;&quot;&#125;,&#123;&quot;name&quot;&#58;&quot;D&quot;,&quot;visible&quot;&#58;true,&quot;width&quot;&#58;200,&quot;sort&quot;&#58;&#123;&#125;,&quot;filters&quot;&#58;[&#123;&#125;],&quot;pinned&quot;&#58;&quot;&quot;&#125;],&quot;scrollFocus&quot;&#58;&#123;&#125;,&quot;selection&quot;&#58;[],&quot;grouping&quot;&#58;&#123;&#125;,&quot;treeView&quot;&#58;&#123;&#125;&#125;</div>"       }     ]   } } 

So why? The SharePoint show it correct… So why the REST API must encode it? -.-

Thank you in Advance for any ideas!