As u can see with the image i posted- I drew the infamous Mr Hyde in four styles that I personally use.
As an artist, illustrator specifically, it's important to diversify ur talents and styles as much as possible- this will only make you more versatile as an artist and all that more valuable in the commercial art world
Having multiple styles for an interested, potential client to look at increases your chances of being commissioned ad of grabbing other parties that might otherwise not be interested in one style
Of course, hand in hand- make sure whatever styles you choose- you can handle! Practice practice practice- understand the principles behind each technique
To get one thing straight in all this- we all learn from each other. Studying other artists resolutions/styles is just like reading books- so much info in a single piece- I'm NOT telling u to copy a piece point for point, but just like studying different fighting techniques- Iearn what u can to better prepare urself.
And the neat thing that results from all this artistic Kung Fu is u start subconsciously meshing styles to come up with ur own selection to choose from- becoming the Bruce Lee of ur own drawing world- HEEE YAH!