Thank you for this insightful post @ogoowinner.

Is holding on to hope a good thing?

I'd say YES!!!
I will start with 3 words; Hope, Unrealistic expectations and Miracles. These 3 words have a thing in common which is EXPECTATION.

The end result only depends on how it is applied.

The basis of Hope is "Optimism"; being full of expectation for the occurrence of an event, but there is a thin line between having an unrealistic expectation and praying for a Miracle. One only has to draw a balance between all these.
At times we refuse to act based on the little information we have about a particular thing, but we hide under the word Hope, maybe expecting change or someone else to act on our behalf. I've fallen for this kind of situations a lot of times.
In all, I still feel it's good to always Hope especially for the best.
Thank you.