Portability, accessibility, etc. "Because it's hard" is never a good excuse to not do something.
Well that's certainly not true in the general case.
"Because it's hard" is a cop-out.
"It's too hard to accomplish given constraint [X]" where X is a deadline, financial constraints, or other real/tangible resource limitations might be one thing. But if you're working on your own timeline on some sort of open-source project, or there is nothing external preventing you from acquiring the expertise/resources to conquer the hard problem, then "Because it's hard" is an absolutely shitty excuse to not do something.
That said, if it makes sense for your project, make it happen! :)
I'm not trying to convince you you don't need it or shouldn't do it, I was looking for a datapoint about what you find valuable in OpenCL.