its hard to make realistic a curve shot .., same about jump

Dunno about jump shots,  but swerve, and even a jump shots, I assume, would have mathematical values, depending upon where you hit the cue ball.

Swerve would be useful. Bit of side heps you out. You can play the correct side and elevate the cue but - nothing happens. Someone would have to program it in.

Jump shots are foul shots in most billiards versions.

I suppose swerve shots could happen by pushing mouse and pulling back fast with the spin at the side.
Also the jump shots you could push and bring back mouse fast with bottom spin.
Probably easiest way.

Jumps shots are allowed in 8Ball, 9Ball and straight pool

Its not possible on fly or die.Because the physical model is much more simple than in real game. When you make a simple draw on a real game with angle, the ball curves back, its doesn't come back in a straight line. Balls go always straight on fly or die they never curve. It doesn't work like this in reality. even the spin is not working on cushion and there is no deflection.
If they wanted to add that they would have to rethink the all physical model program. Its nothing like a simple update. Adding that would mean much more parameter to fix.
They can't do that it would mean reprogramming all the game.

As a former software engineer, it would be extremely difficult to impliment Masse shots and jumps, but not impossible. the current physics model does have a few flaws as far as spin and deflection are concerned, but the cue ball does react very closely to correct after contact with an object ball. as far as web based pool goes, Fly Or Die is THE closest simulation that has "EVER" been available, and if FOD's current trend continues, I think we will see even more updates and changes implimented that none of us thought would be possible. Deepest Respect to the FOD developers.

curve shots would be useful sometimes and would add a lot of realism.
Speaking of realistic phisics: I would really like to see the balls react properly upon contacting the rails: in RL I guess the balls lose about 8 to 12% of their energy upon contact and it is therefore not possible to have a ball travel more than 3-5 times the length of a table (depending on table size). In FOD 7-10 times is easyli possible.