So, she is a popular actor who made her debut in a lead role in 2002 and still going strong even after nearly 25 years in the male dominated and patriarchal cine industry. She has acted in about 75 films so far in all the four south Indian languages plus Hindi. In Tamil she had acted opposite all the top stars like Rajini, Kamal, Ajith, Vijay, Suriya and Vikram.
Coming to the part of her importance in Tamil Nadu politics, she hasn't displayed any active interest in party politics, barring for an old interview given as far back as in 2004 wherein she had expressed her desire to become the CM of Tamil Nadu in a rather cute and playful way.
Trisha has so far not been a member of any political party, contested any elections like Khushbio Sundar or even campaigned for candidates. So going by her involvement or impact on Tamil Nadu politics her importance as of now seems to be negligible if not nil. Anyway it is nowhere as near to the importance of some other actresses like Kangana Ranaut or Smriti Irani in the Indian national politics.