Michy must understand that Costa is in terrific form right now and it would be weird for Conte to drop him entirely for a young guy with "a lot to learn". When he learns what Conte thinks he has to learn, and Costa stops playing this well, (he can't possibly keep this forever? However if there is someone able to keep this kind of form going for a long time, it would be Costa) he will get his chance.
Also, we all know Costa will get injured/suspended/both this season. Michy has to be 100% ready then and take his chance.