ilus 3 speed smartphones runs jelly bean ( should I buy?)

[AC Question]

Hello I am planing to buy a rarely known ilus3 speed smartphone .. I was impressed about its specification , BUT
the fact that is still runs(((((( jelly 4.2.2)))) make me upset ...
should I still buy it ,, and how long will apps still support Jelly .....
it is a very important for me ..
thanks for reading ....