Popular: easy to understand, suitable for the level and needs of ordinary people.
2. My feeling:
In my opinion, "vulgarity" means focusing on things that have no advantages, even low-level and unhealthy things.
"Fashion" is different. It's a neutral word, but it's not mysterious.
There is always a sense of intimacy.
3. Classify advantages and disadvantages
Order: The popular is the best, and the worst is vulgar.
References:
Modern Chinese dictionary