Since last patch, the bulk of your chance to crit is given passively by rubies, and not by the stat itself which has a very low return over points investment. On f2p server, with guild rubies, holy weapon, artifact scroll, and class rubies you get 228 crit chance. That's somewhat around 18 or 19% chance to crit, so with the passive crit rubies u'd end up a little over 40% crit rate (passive rubies give 20 or 25% extra crit chance, not online to check atm). You could put another item on crit chance, sure, for another 1-2% chance of crit, but it would simply be more profitable in any other main stat.
That said, crit dmg is what makes crit chance worth having at all, especially in pvp, since unlike crit chance, it is the special stat with the highest return, if you crit.
Let's say you crit 40% of the time. You have 200 profi, and 250 stats points to invest. Say base dmg is 1k. 1200 with the 200 profi. Investing 250 stats on crit dmg you would get an average dmg output of 2016. Investing them on profi, it would be 1740. Investing 50 on profi and 200 on crit dmg would be 1996. Investing 100 on profi and 150 on crit dmg would be 1934. So the sweet spot for crit dmg is 250, if the alternative is proficiency. In pve, determination has still a higher return. I'm intentionally leaving out double attack, as it makes no sense dmg wise, it's being used purely for class mechanics purposes.