You can't do this directly, but you can use a "Repeat" to chunk one big, quick, movement into lots of smaller ones. Control the speed by changing Local_granularity -- smaller is faster:
Mouse Move Controlled.kmmacros (3.7 KB)
Extending that to curves etc is "just" a question of maths... Have a search on the Forum if interested.
You could also try the CLI utility cliclick, though I think its easing option uses the same basic mechanism.