"336 hours vs. 90 minutes for a diurnal cycle."

In a dark crater near poles, there is no cycle. Constant temperature [no thermal cycling]. Constant observation- though even if located at equator region, you have constant observation because there is no atmosphere to scatter the light. And the platform is fairly stable relative to Universe you are observing [unlike earth which rotates every 24 hours or unlike low earth orbit which orbit every 90 mins].
BUT we generally don't mean only LEO when referring to orbiting telescopes- newer telescopes are being planned for Earth/Sun L-points. An optical telescope at Earth/Sun L 2 will have similar advantages as you would have on the Moon. And you could choose to look at any portion of the sky except where the Sun is [on the lunar surface the portion of the sky at any one time is more limited- though if you are located in a dark crater it would be impossible for telescope to accidentally be pointed at the Sun. And because a multi-billion dollar telescope will not risk getting near to being directed at the sun, the telescope is as result is "blocked" from looking in this direction- and despite this safeguard, there is always a possiblity that something will go horribly wrong and resulting in telescope looking at the Sun. On Moon it would be possible to safely look nearer to the Sun.

But with question of Orbital vs Lunar suface. Questions about how big a telescope is required and any plans to do maintenance would be important considerations. E.g. is the telescope in question small enough to fit in the payload of a rocket launch- Earth observatorties would be quite limited if they had to be fitted inside a semi-trailer truck [not to mention requiring them to robotically deploy at it's destination].