EDIT: Something tells me I really misunderstood the concept of death counters. Gonna try another quick thing and re-edit this post.
I haven't actually looked at the triggers in your post, so don't take this as an interpretation of what you've done.
I think death counters are confusing for a lot of people because they are distinctly used for two different, but related, concepts in mapping.
At their most basic, death counters can be used to replace switches, and to replace waits. Effectively this works like this:
Replacing a switch: DC has value of 0 (false) or 1 (true)
Replacing a wait: There are approx 12 DCs per real-time second at Fastest game speed, so if you have a trigger that is "Always: Add 1 to X DC", then when X DC is exactly 12, one real-time second has passed.
DCs are actually more powerful than simple switches though. With switches, if you wanted to have 4 possible outcomes, you'd need two switches with different combinations of truth values: TT, TF, FT and FF. With a DC you simply have 4 possible values: 0, 1, 2 or 3. You can easily expand this out to 20 possible values, just using 0 to 19 (or 1 to 20), whereas with pure switches you'd need at least 5 different switches (2^5 = 32 outcomes), and you'd have to deal with all of the 'extra' outcomes that you don't have specific cases for.
You can also combine the switch behaviour and the timing behaviour into the same DC. For example, you can have triggers like this:
Condition: DC is at most 12
Action: Subtract 1
Condition: DC is exactly 0
Action: Create unit (or whatever), set DC to 12
Condition: [Something happens that we want to stop unit creation]
Action: Set DC to 20
With these 3 triggers, we would initially set the DC to be 12, and it would create units (or whatever), every real-time second. Then, if we wanted to stop spawning units (player moves marine onto a beacon, or whatever), we can set the DC to 20 and that will stop more units being spawned. If we wanted to start spawning units again, we could have a 4th trigger that set the value back to 12 (or 0, or anything less than 12 really).
There are only three advantages that switches have over DCs:
* Switches can be randomized - the only decent source of randomization available for use in triggering
* Switches can be easily flipped from true to false using "Toggle". You can get the same behaviour out of DCs but it's a bit more fiddly / requires more triggers to do.
* Switches don't correspond to real units in the game. If you have an 8 player map where all players use all playable units, and they can die, then you'll only have a limited number of DCs to work with, but it is still quite a generous amount.
None.