Radicals have certain meanings in Chinese. For instance, as for the following Chinese characters, 讲,说,话, 诫, They all have the same radical which means this character has something to do with talking. That is to say, if you understand radicals well, you can imagine what a character means even if you don't know it before. Hope it can be of a bit help.

if to consider "radical" is an index part of a symbol like 扌in 招 you need to know it in order to find an unknown symbol in the dictionary when you see 招 you will be looking it by 扌, not by 刀 or by 口 otherwise how do you know the meaning and the reading of 譬 or 籍?

借助于部首，我们可以推测汉语生字的读音和意义，并能加强对汉字的认识，理解，记忆。 汉字部首的作用类似于英语中的词根。