I assume you mean using a stacked dado blade. Dados can be done with a track saw, it takes longer since blades can't be stacked, but it's doable.
Can you explain what you mean by custom coves? Im guessing you mean dragging material unguided by the fence at an angle to the blade spinning?
Don't get me wrong, I'mm not anti table saw, I have on and use it often. The OP is asking if he "NEEDS" a jobsite table saw. If portability is the REAL issue, I think I'd rather have a Track than table saw for in the field.