Nets are used poorly by bowlers.
The net is the "Swiss Army knife" of cricket training: Players who stick to just using the knife are ignoring the screwdriver, corkscrew and bottle opener at their cost. With the right drills, nets develop technical, tactical and mental skills as a bowler.
But it doesn't happen by magic. If you turn up to nets, wait for your chance to bowl and fire a few balls down for the batsman to slog you won't get better at bowling. In fact, the best you can hope for is just to stop from getting worse.
So don't waste net sessions. Use the right tool for the job.