The point is to discourage others from doing the same. It's a classic SLAPP lawsuit.
Some federal circuits (e.g. the 9th) have protections against SLAPP lawsuits. The 5th circuit (where this lawsuit was filed) does not, and the district judge is Reed O'Connor (https://en.wikipedia.org/wiki/Reed_O%27Connor) who's infamous for rulings friendly to conservative causes.
If it gets to that point, yes. There are multiple places where the lawsuit can end before a jury enters the picture (dismissal and summary judgement being more prominent examples), and in those cases it's the judge making the ruling.
The insinuation here is that the venue was chosen to get a judge that is less likely to rule against X/Twitter in those earlier stages and make it more likely that later stages of the trial will be reached.
Some federal circuits (e.g. the 9th) have protections against SLAPP lawsuits. The 5th circuit (where this lawsuit was filed) does not, and the district judge is Reed O'Connor (https://en.wikipedia.org/wiki/Reed_O%27Connor) who's infamous for rulings friendly to conservative causes.