If you are not taking an exam, this is still useful
Yes, even if you are not doing an exam, focusing on these parts of English is still very important. It is important for your accuracy to practise these parts of English separately sometimes.
Here are some videos to explain. The first video shows a martial arts drill. A drill is an exercise of repetition, where only one action is practised and repeated again and again so that the student can focus and improve on one specific area. This is not an authentic fight but it is an important part of martial arts training.
Martial Arts Conditioning Drill - Shield Target
You can see that this action alone would not be very useful in a fight. However, when you put this action together with other actions then you can get something like this! (One of the most exciting martial arts fights I’ve ever seen!)
Jackie Chan - Who Am I - Last Fight
Note: the above link is no longer available. Try this instead:
"Jackie Chan, Greatest Fight Ever" http://www.youtube.com/watch?v=HVsigkUmvy8 20 Dec. 2012.
So from this martial arts example, it is easy to see that the same rules apply to language learning. You've got to do the drills, practising your conditionals 'over and over and over' (meaning again and again and again), practising your use of passive voice over and over and over, practising your comparatives and superlatives over and over and over. This way they become better and better, you use them with more accuracy and fewer mistakes.
Then when you put them all together you get a grammatically accurate piece of writing or a grammatically great conversation.
Gordon. "Remember: English for Exams is not Authentic." Understanding How We Learn: Observations, Opinions, Suggestions and Recommendations for Learners of English. 31 Aug. 2011. Web. 31 Aug. 2011.