This is Microsoft's own statement:
"Microsoft announced the end of life of Silverlight 5 in 2012. In 2013, Microsoft announced that they had ceased development of Silverlight except for patches and bugfixes. Microsoft has set the support end date for Silverlight 5 to be October 2021.[6] Silverlight is no longer supported in Google Chrome since September 2015.[7] Since Microsoft Edge does not support plugins, it also does not support Silverlight"
It is still included in 10, for companies and private individuals who have committed to it. But MS are asking users to discontinue it when convenient. You can certainly remove it, without ill effect.