To illustrate its necessity, I’d like to list several example here, for us reference.
Example 1: In fact, the intriguing flavors of the creation come from the spicy oil.
[Original Trans]: 事实上，这诱人的风味完全是辣椒油的功劳。
[Updated Trans]: 事实上，这诱人的风味完全归功于辣椒油的功劳。
The original Trans is without any error in Chinese, but if ‘是’ is replace by ‘归功于’, to read the whole sentence is more fluently in Chinese. Thus, if the translator could read the translated file, he/she would find this point and make change to it.
Example 2: Indeed, summertime is the perfect season to have such a delight.
[Original Trans]: 夏季则是品味秦镇凉皮的最佳时节。
[Updated Trans]: 夏季则是品尝秦镇凉皮的最佳时节。
For this sentence in the translation, it would be more acceptable to use ‘品尝’ not ‘品味’, so being the translator, should always keep in mind to choose the appropriate lexicon to convey the actual meaning in Chinese.
Example 3: Moreover, cumin, anise, pepper and fennel are the most common spices that are used to enhance flavors.
[Original Trans]: 此外，最常采用的香料是小茴香、八角、辣椒和茴香，用来提升美食口感和香味。
[Updated Trans]: 此外，最常采用的香料有小茴香、八角、辣椒和茴香，用于提升美食口感和香味。
Comparing the Original Trans with Updated Trans, as we could see, to read the latter one is more fluently in Chinese, and more comply with Chinese saying.
Example 4: The sublime experience of appreciating the delight is almost too good to be true, even for someone who is not fond of alcohol like me.
[Original Trans]: 这种难得的经历实在是太美妙了，让人难以置信，甚至像我这样平时不嗜酒的人也不由得赞叹一番。
[Updated Trans]: 这种难忘的经历实在妙不可言，让人难以忘怀，以至像我这种平时不嗜酒的人也不由赞不绝口。
For the Original Trans, though it basically conveys the source meaning, however, some lexicon choice in Chinese are not quite appropriate, if the translator could read the translated file after translating, he/she would choose the better lexicon in the translation, so the translated file seems more fluently.
So in my opinion, it is essential to for the translator to read the translated file after translating, to avoid choosing the unsuitable lexicon in the translation.