Welcome to FT, OP.

Before getting to the question of if DM is worthy or not, you have to understand that all upgrades (regardless miles, op-up, as well as the NA's style upgrade instruments) are subject to capacity control. No airlines ever is able to guarantee your upgrade at all.

The rest of the benefit, give or take, are pretty much standard elite benefit (although I do agree some people may value blocked seat, bottle of water, as well as personal greeting a lot).

So here is how you should look at this issue:

1. If CX's DM does not worth the effort and money, which airline do you want to try out or even switch partially or totally? Remember - not all program are suitable for you.

2. After the switch (in theory), what do you gain that you can't from CX (like upgrade instruments, bonus miles)? And what do you lose in exchange (for sure - no more water, personal greeting, first class lounge...)?

3. Are you really in a position that you can bargain? For example, if you are HKG-based, and you mostly fly to the U.S., then the obvious substitute for CX is UA. Is UA really what you want?

You know FT - we are like a big family. So feel free to ask other forums and see if this is a choice you should make.

No one can value the importance of DM except yourself - as you are the one who use it (And this is one of the reason why I am stuck with UA - as I don't have a choice...really.)