Although looking similar, they have different looks and personalities. Talented and capable idol celebrity siblings have simultaneously entered the South Korean entertainment industry in recent years.
When one talks of celebrity siblings, the first image that comes to mind would be Girls' Generation Jessica and f(x)'s Krystal. Jessica made her debut in 2007 as a Girls' Generation member, and she was followed by Krystal 2 years later as she debuted with f(x). Krystal grabbed much attention prior to her debut after it was made known that she was the younger sister of Jessica. The Jung Sisters belonged to the same management agency and went through a tough period as trainees together. They were a pillar of support for each other, and their sisterly bond became even stronger along the way.
Another representative pair of celebrity siblings would be 2NE1's Sandara Park and MBLAQ's Thunder. Since his debut, Thunder has frequently been labeled as 'Sandara's little brother', and thus she became a huge contributor in promoting the name of MBLAQ along the way. Thunder has now walked out of his sister's shadow, and is now a representative member of an idol group that leads the Korean Wave.
The Jung Sisters (Jessica, Krystal), and Sandara/Thunder siblings were a good example of how celebrity siblings would be of huge benefit in the entertainment industry. 3 to 4 years back, if one was to make his/her debut first, he/she would be of great help and support to his/her sibling later on. You would get a lot of hints from your sibling, and also assistance in the form of opportunities and more to help adjust to the entertainment industry in a quicker manner.
But the huge influx of celebrity siblings recently have led to a cold reaction from the public, as the novelty factor is no more. You might be able to gain recognition in a quicker manner by tagging a brother/sister label along with your name, but the effects are not as great compared to the past, and won't work in the long term if you lack the talent.
D-Unit's RAM (Jeon Wooram) was able to get her name recognized early in her career because her father was former singer Jeon Young Rok and her sister is current T-ARA member Boram. But she did not rest on her laurels and went independent of them, and is now doing everything on her own and slowly adjusting to the entertainment industry at her own pace.
There's also many celebrity siblings that aren't that known by many. Solo female singer JOO and BtoB member Jung Il Hoon are siblings, but few people knew of that from the beginning, so Il Hoon has practically been on his own since his debut without any help rendered from his sister.
Not many know that Block B's leader ZICO is brothers with upcoming boy group SPEED member Tae Woon. If it was a few years back, Taewoon would definitely be debuting with the label of 'Zico's brother is making his debut'. But nothing of that is being done now, which shows that the trend is dying off.
In the past, the public would find it interesting to see celebrity siblings appearing on the same television screen. But with more and more celebrity siblings appearing now, the novelty factor has worn off and it just doesn't hold the same appeal as before. It's an era when you really have to rely on your talent to get by and not through your family ties. The talk of celebrity siblings is now surely a thing of the past.