1- yes, the French enjoy protesting. It is a national sport.

2. They aren’t considered serious until the Unions go on strike. When one Union goes on rstrike, they ALL go on strike

3. After about 2 -6 weeks of a strike with no public transportation etc, something gets negotiated and the strikes and protests end.

4. Have they been effective? From time to time they have. Look up May 68. Protests nearly brought the government

Look up 1995 French strikes (which I witnessed)and the 2019 pension strike

"The Democrat Party looks like Titanic survivors. Partying and celebrating one moment, and huddled in lifeboats freezing the next". Hatari 2017

"Hokey religions and ancient weapons are no match for a good blaster at your side, kid." Han Solo