The reason a "DG" is important is very common: 90% of officers (pilots) are equal in piloting ability. It's the OTHER stuff you do that gets you stratified amongst your peers. Everytime you are in a group, you are competing for stratification--be it at ASBC or in the squadron. You belong to the group of "copilots", or "wingmen", or "tactics cell", or "training shop", or "SELO" or "SDO", or even SNACKO. Makes no difference. Your SQ/DO and CC are looking for ways to tell you people APART. Why is chucklehead X better or worse than chucklehead Y? They both got Q1's on their checkrides and didn't screw up on their first deployment and are progressing normally through upgrade. How do I tell them apart? The answer comes in all the OTHER stuff you do to enhance my unit's effectiveness: administrative excellence/morale booster/unique program management/inspection preparation, etc...that's what the CC needs help with--UPT and IQT do a good job of making you a good technician with an OK skill set, and our training shop has a program to get you up to speed on the mission...so since you're all equal in those regards, I need to know what ELSE you bring to the table to differentiate you from all the others...
ANYTIME you get a chance to distinguish yourself from your peers (by getting a DG, Top 1/3, #1/3 Asst execs, etc) this helps BOTH the CC decide who to go to bat for (early upgrades/choice PCS/another flying gig) and who to send on less desireable assignments, or even to approve the bonus $$ for. Works in reverse too--the copilot who gets two DUIs in a week probably wont get to go to SOS in-residence...Know the rules of the game you're playing. Blow off ASBC and you lose a chance, perhaps five/ten years from now, to attend WIC, or go in-res to ACSC- because the dude you're competing against THEN got the DG from ASBC, and that became the CC's deciding factor on who to send. It happens.
Since you don't KNOW for a FACT you're separating at the end of your commitment, or you're on track for CoS, might as well learn early the rules of the game your playing, and do everything possible to set yourself up to be a contender for WHATEVER job/career goal/aspiration you have. Get off course, even a little, and your decision maybe gets made for you and you lose options. Whether you want to be a SQ/CC or a terminal iron Major with 25,000 flying hours, or separate ASAP, you should probably try to garner the same distinctions every chance you get. You'll either make your goal and be a CC, or make your goal and turn down Lt Col, or make your unit CC cry when you separate. But the key is, it was YOUR CHOICE every time. Fail to follow the rules, and you don't get to choose.
Its your life and career--work it any way you want.
/off soapbox...again...