The combination play only lets you play combinations of 5,7,8 or 9 numbers. If you have some numbers that you are
really sure of this way of playing will
guarantee that you have the winning combination if you pick all 6 numbers correctly.
The only one of these I might play is the 5 number combo where your five numbers are combined with each of the remaining 44 numbers. However, at $88 its a 'lotto' money.
It would be preferrable if they let you pick one 'key' number which would then be randomly combined with all of the other numbers, 5 at a time. This way you could cover all of the 49 numbers in 10 tickets. Or, with 2 key numbers it would take 12 tickets. Of course, these are easy enough to create on your own.