Making Thrassians Desert Creatures

Ok so in my world the Nar (Thrassians) are a desert species instead of an aquatic one. I was thinking of swapping out their swimming ability for desert survival type of ability. Since it’s a three point ability I was thinking maybe something like:

Can go two weeks without water.
Survive in high temperatures without becoming fatigued.
+2 to saves versus fire based attacks.

Does this seem worth the 3 custom powers? Are there better options?

Maybe an ability to burrow quickly into sand (like a real-life Sandfish lizard)? A bonus to surprise rolls in desert settings? a Sneak ability in desert/sand settings?

And being able to go two weeks without water could be a very powerful ability if your actual campaign is set in the desert, but much less powerful if you intend to play in temperate areas where water is much more common. Maybe being able to survive without water AND food with no penalty for two weeks could be far more useful in all settings…

Well, that’s the thing. Being a great swimmer is awesome…if there is ever water around. I think it’s come up in maybe 3-4 sessions (most of those part of the same adventure). The desert thing only recently came up, but basically forced me to remember that the creatures were always meant to be desert creatures, I’d just used the Thrassian template from laziness and not changed it. But now they are in the desert and so it’s a ‘thing’.

You make a good point, a week without food or water is a big deal no matter where you go and maybe that is worth 1 custom power. I hesitate to go with the sand burrowing, though it is kind of cool, just because they are still humanoid (and larger than humans typically).

In old-school type games with strict accounting of provisions, being able to go without food and water for a week is a great boon, and also fits the desert theme very neatly.