Optimism, no. I live in the area. We are going through a record cold snap, as in literally the lowest every temperatures recorded in some areas. And yes, the coral loves the respite. It's been accompanied by record floods, doing a record amount of damage. Which is to be expected - it's the La Nina pattern.
But record low temperatures, in a time when the base temperature is up 1C? That means the "other prediction" of climate change is coming true. The extremes are getting more extreme. And it's not the warming that's hurting us or the coral really, it's the extremes - just a few continuous days in a year when the temperature is +5C. That's what kills the coral - not the 1C average rise.
The reef isn't shrinking because the temperature gets so high it can't survive. That's always happened periodically. Once it gets that high it doesn't matter whether it's 1C over what the coral can tolerate, or 10C, or lasts for a couple of days or a month, the outcome is the same - the coral is dead. But if the high temperature is followed by 5 years or continuous growth, the coral re-colonises the area. What's been happening is we have been hitting extreme temperatures (both low and high) more often, and because the highs are more frequent the coral doesn't get a chance to grow back.
Remember those bush fires Australia has a few years ago - they were the worst we've even seen. Now we are laying down another fuel load. And it looks like the La Nina will persist for 3 years - another rare event, so the size of this fuel load will be another extreme. This cold snap will be followed by another record hot period, and we will move from losing billions to floods to losing billions to fire, again.
I'm not optimistic. I'm fearful.