Probably for the same reasons that when a fictional Mr. Xǔ Zhì Qiáng (許志強) settles down in beautiful America, he goes by the name “George”:
- To better-assimilate into the culture and environment of his new home
- Because 8 out of 10 persons probably cannot figure out how the heck to correctly pronounce his name, what with the X, Z and Q in it.
Okay, that was a bit tongue-in-cheek. But you get what I mean. Likewise, things will pan out a lot easier for a Mr. Bonaventure Featherstonehaugh in Shanghai if he just went by a simple “Mr. Huò Běn” (霍本).
Okay, real example – meet Mark Henry Rowswell, celebrated Canadian comedian based in China:
His name transliterated in Mandarin comes out as 馬克·亨利·羅斯韋爾 Mǎ-kè Hēng-Lì Luó-Sī-Wéi-ěr. That’s 4–5 characters too many by Chinese standards. Nowadays, he just goes by the name 大山 Dà Shān, lit. “Big Mountain”.