I noticed that《汉语大词典》opts for 風景綫 over what most other reference works write as 風景線.
KEY does mention that 綫 is a:
1 (variant of the more commonly used xìan 線) line, thread, wire, string
zisea also seems so say that 线 is:
【綫】的简体字。拼音xian4
zisea on the other hand only says that 線:
①同【线】。
線 is treated more like a variant than the actual traditional character for 线. But this all seems quite contrary to my understanding for this character.
Is there a viable reason why 綫 would be picked over 線?
My understanding is that when characters were being simplified in Mainland China, they first had to standardize traditional characters (i.e. What should these new characters be simplified from?). 「綫」 was chosen as the traditional standard, thus in the PRC's Table of General Standard Chinese Characters (通用規範漢字表), you can see that 「线」 is considered to be simplified from 「綫」, while 「線」 is listed as a variant of 「綫」 (「缐」 also exists, but is only used as a surname).
Understandably, if the dictionaries you are using are Mainland Chinese, 「綫」 will be treated as the standard character rather than 「線」.
In contrast, every other region in the Sinosphere that has some standard for Chinese characters (i.e. Hong Kong, Taiwan, Japan, South Korea) list 「線」 as the standard form, which might explain why 「線」 is much more prominent outside of simplified Chinese.
However, as mentioned in the other answer, 「綫」 is quite common in Hong Kong, despite 「線」 being the standard character in Hong Kong's List of Graphemes of Commonly-Used Chinese Characters (常用字字形表). This is likely because the standardized character shapes are used as general guidelines for education, rather than used as a strict set of rules to follow.
The smaller character here indicates a variant form.
Both these forms have existed as variants of each other for quite some time before the modern era, so aside from regional standards and popularity, one isn't necessarily more correct than the other. I'm not sure about Japan and Korea, but in Chinese-speaking regions, both forms should be equally well-understood. In the end, it boils down to personal preference.
There probably isn’t a preferred choice between 線 and 綫.
In Hong Kong, traditional characters are used. The MTR Corporation officially refers to their MTR lines as XX綫. However, if you take some feeder minibuses, they will often refer to those lines as XX線. This means both characters can be accepted as “official”, since they concurrently appear on various public transport signs.
(Not enough reputation to comment, so I am posting this as an answer instead)
In addition to MTR's example,
TVB uses "綫": 無綫電視/無綫新聞台
But another company, i-CABLE TV, uses "線": 有線新聞.
And "wireless" in "wireless network" is usually written as "無線".
From my observation, nowadays people usually write "線", and "綫" is only used in very few cases.
