I just wonder when i ascend hp and defend champions type and all their skill damage based on hp or defend only, i just keep getting attack upgrade. Is attack value useful to these champions? If no, shouldn't we recieve only hp and defend for these types of heroes instead? I mean at least defend still be useful for hp type champion 

Sorry for my English.

When you ascend, HP/DEF/ATK are all increased.  

You need to check individual hero abilities - there is a tool tip that says: Damage Scales with [Attack]   or [HP]  or [Defence]  or something else.

This is what is useful. If they all say [A], then [B] is not useful whatsoever 

It sometimes only increased hp and atk or atk and defend. Not all 3 values always increased at a time till you ascend at maybe 3 or 4 stars. 

Last time i ascended a champion with all skill damage scale with hp and i got hp and attack upgrade. So i just wonder if attack is helpful in this hero at all? Shouldn't i get defend instead of attack?

Which hero?  Your gear is far more important - gear him/her right.