A common problem that you might face when teaching students to read by sounding out the words is that often a word doesn't follow the phonics. Words like 'do' and 'go' have a different 'o' sound. Take for example the letter 'a' we teach kids to think of 'ants on the apple - a-a-a' but in some of the sight words like 'what' we pronouce the word differently (not wh-aa-t).
The goal of the common sight words is to remove this difficulty by having the student recall the sound of the word by sight, rather than deal with the inconsistencies of sounding the word out. Over time as the student nears the common 200 threshold, they will be able to read more fluently and not think about all of the weird cominbinations of words.
In the long run students that have a good command of the common sight words will have an easier time reading. Our sight word apps helps students master these common words by providing a range of different games and activities that help students hear the words and match them to the written representation.