Just finished watching season three of The Bridge, which features subtitles over the spoken Danish/Swedish.
This isn't something I care about because the show is shot in Denmark and Sweden and stars Danish and Swedish actors. Even though I can't follow word-for-word, I enjoy their performances because they are speaking in their own languages. It takes little from my enjoyment of the show.
In Discovery, that's not the case. These are regular actors forced to deliver long speeches in a language only a smattering of people actually understand. I can tell they aren't comfortable reading those lines.
This is nothing to do with laziness on my part and everything to do with poor decision making. The only real reason for them to speak Klingon is 'authenticity' and perhaps making them seem more alien.
Firstly, 'authenticity' doesn't seem that important in this kind of show. Secondly, they already seem alien enough through character decision.
In fact, I'd argue the use of subs is laziness on the part of the creators. Klingons might have looked different before, but they used to distinguish themselves through how they carried themselves, how they spoke, and the views they espoused. That's what made them seem alien, and it worked way better from a storytelling POV. You could argue that having them look really out-there and speaking in Klingon is just a lazy way to make them seem alien.
And even if you accept the authenticity and otherness, is it really worth it for such stilted, incomprehensible dialogue?