as one would expect from ...; given that ... (used to express admiration or praise)
世界的なピアニストだけあって、演奏は本当に素晴らしかった。
As expected of a world-class pianist, the performance was truly wonderful.
プロの仕事だけあって、仕上がりが違う。
Given that it's a professional job, the finish is different (better).
彼女は毎日走っているだけあって、足が速い。
Given that she runs every day, she is fast.
for good reason; there is a (good) reason that ...; it's understandable given ...
彼は十年も研究してきただけあって、説明が詳しい。
He explains things in detail, which is understandable given that he's researched it for ten years.
老舗の店だけあって、サービスが行き届いている。
It's an old-established shop, so the service is attentive.