Using various functions and structures with infinitives as well as gerunds allows you to demonstrate your grammatical range and accuracy.
Remember the use of the infinitive as a subject, though correct, is not commonly used and especially not in spoken English. In IELTS and academic writing it is more appropriate to use the it subject instead. Remember also that infinitives of purpose using so as and in order are more formal structures.
Study English - IELTS Preparation, is a series of English language programs for intermediate to advanced learners.