Free SMS for Gmail users isn't a great idea

Google has just announced free SMS for free and paid Gmail users. The users will be given 50 credits. Each credit allows the user to send a SMS and for every reply 5 credits are added. The total credit would never cross 50.

Not officially confirmed but Google has launched this service in association with 2 tier cellular operators in the country like Idea, Reliance, TATA etc. While Airtel, MTNL, Vodafone are not yet available. The SMS sent out would get directly received on the mobile handset, however SMS received would land on the Gmail chat window. Which means you got to be always hooked to your Gmail account.

It is a good move by Google to increase the time spent by average user on Gmail. However, I think Gmail hasn't got their strategy right with this one. Let me explain. The biggest revenue model on which Google strive is Ads and the users of such a SMS service would be people with lower purchasing power like collegiate etc (who can't even afford regular mobile recharges). Now even if ads are shown to such people, the CTR (click through ration on ads) would be extremely low or wrongly targeted (income wise) even if the Ads are contextually right. For ex - An ad gets delivered to two friends discussing latest songs that they downloaded on their smartphone. The ad server will pick 2 keyword songs and smartphone and then throw ad related paid songs download website or latest smartphone ads. Now, these ads are contextually right and people might click on it as well but in terms on pocket size (affordability)  they are wrongly targeted and not enough conversions would happen. Hence, brands would not get returns on their ad investments at such places.

Above is just a thought, results might be different from what I think. What do you say?