REAPER does not use automation curves in the MIDI editor, but as Lokasenna pointed out, you can do pretty much the same thing (and
much more, in fact) using REAPER's MIDI editing scripts.
With regard to MIDI editing scripts, check out the threads:
MIDI editor tools: warp, stretch, deselect etc, and
LFO Tool for MIDI editor and envelopes. The following GIF demonstrates some of these actions, using toolbar buttons:
And the thread
Velocity/CC Tool
And the thread
Reascript by Kawa, which links to
Kawa's MIDI scripts.