The Helper Connoisseur / Ex-MineCraft Host
Summed up by /u/LukyLucaz :
For those who don’t understand why these workers go on strike since they’re supposedly all going to be laid off anyways, let me explain:
In France, as in many other European countries, you cannot just willy nilly decide to close down an office and turn 300 people jobless. By law there are certain conditions that must apply before you’re legally allowed to do so. Unions (who have relatively more power in Europe than in say the UK or US) tend to fight massive lay-offs like these and have even won court cases against employers, forcing them to cancel lay-offs like this.
Second, even if the lay-off is inevitable the strike could prove useful. Blizzard would ofcourse like to lay off most of these people on their terms. Should the unions fail to prevent a lay-off alltogether, striking may succesfully force Blizzard to the negotiating table and serve to levy strenght in the workers favour there, perhaps guaranteeing them better severance conditions.
TL;DR: Union activity (such as strikes) can potentially cancel a lay-off. If not, the strike could force Blizzard to agree to better severance conditions for the workers.