The seemingly discontinued Airtel SIM chips are better suited to Airtel's latest 1GB special offer for N200. I tried one of my old SIMs and it was eligible. It may be expanding over time to the latest SIM cards.
However, you can keep your SIM chip for 30 days without using it and you will be automatically be eligible for the offer. The offer is juicy as with MTN and I bet it will be useful to those who do not want to spend a lot of money surfing the internet.