Pros:

• Don't have to install any softwares on your PC
• Can run straight from the browser
• great for beginners who wants to learn
• users can make use of their webcam + mics on their pc
• being a .js file, users may be able to use it on mobile platforms as well
• users who have tensorflow background can apply the same ideas to tf.js

Cons:

• webgl is definitely slower than traditional python AVX
• js might not have all the libraries which are common in python