This is really interesting. An end user company has switched from a 4L .com to a 5N .com.
BXGB.com (不锈钢帮 a gang of steel products) was a B2B steel products website but it seems to me that the company has sold BXGB.com recently and switched to 16889.com. BXGB.com has a different registrant and the website now provides logistics services.
The reason for the change, according to the company, is that 16889 is easier to remember than BXGB because 16889 can be remembered as it is but BXGB must be converted first to Pinyin (Chinese characters), thus requiring an extra step.
Yes, I agree 16889.com is relatively easy to remember, but BXGB is not bad either. I'm still not convinced that 5N is easier to remember than 4L.