Special Cover - Centenary Year of Mahatma Gandhi's Return to India

Do you think special cover makes any importance in your stamp collection ?

I think it's nothing but useless collectibles because it's a special cover to MAKE MONEY.!! for philatelic society or association and dealers who wants to sell it on internet and philatelic.

Recently India post issue miniature sheet with 2 stamps of Mahatma Gandhi to celebrate Centenary Year of Mahatma Gandhi's Return to India.

Also FDC was issued by Post & Telegraph department of India with this stamps.

But what surprise me is the SPECIAL cover issued by various philatelic association.!!

Look at following Special Cover issued to celebrate Centenary Year of Mahatma Gandhi's Return to India (1915 - 2015).

But does it make sense to collect.!!

This covers are selling for than $5-$10 on eBay as well from philatelic association. This cover cost less than $1 to make so it's a good return on investment.

So what do you think about Special Cover - Centenary Year of Mahatma Gandhi's Return to India ?

Does it make sense to collect SPECIAL cover ?

Thanks
GSC.