How would a motion to strike be useful?

I am involved in a summary process due to nonpayment of rent by my tenant. The tenant included a special defense in the answer to the complaint. Item (3) in CGS 47a-20a states that an action is not retaliatory if "the condition complained of was caused by the wilful actions of the tenant or another person in his household or a person on the premises with his consent." And Mobilia, Inc. v. Santos, 4 Conn. App. 128 (1985) agrees that nonpayment of rent is not retaliatory under this statute. I am trying to understand how a motion to strike this special defense might be better than raising the issue during the trial. One drawback I see is that according to the Conn. Practice Book, "Any adverse party shall have thirty days from the filing of the motion to strike to respond to a motion to strike," which would add a delay. Thank you for any information and insight!