Conjunction connects two words or two clauses or two phrases.
70 useful sentences for academic writing
This page is about linking words and signposting. It is fine to learn linking words which are part of coherence and cohesion. It is NOT good to memorise phrases for IELTS. See all tips on this page:
Christine, I appreciate your kind words
Yes. There is a criterion for marking which states that if you overuse linking words or if you use them mechanically (this means without flexibility), your score will not go higher in that marking criterion. This related to Coherence and Cohesion which is 25% of your marks for writing task 2. See my advanced lessons if you need training: