Ask HN: Are there any downsides in using img-based tracking with Facebook?

The standard solution for Facebook sales tracking is having a JS snippet that loads _something_ from Facebook. However, the snippet also contains a <noscript> section that provides an example of tracking the same data with a simple 1px image tag.

The JS snippet is problematic both from the privacy standpoint and also because it's overhead is way bigger than 1px image. Why people continue injecting FB JS code into their pages? Are there any downsides in using the img-based solution exclusively?