Throwing both a slider and curve

Ok I have a bit of a question…I’m in my first year at a mid-level d-1 after playing juco ball, I throw an 88-91 mph fastball, and a solid 12-6 curveball, both of which I can throw for strikes consistently. My change-up on the other hand is very inconsistent and I’ve had trouble even throwing it for strikes. Some days i can get it working but i really don’t have much confidence in it. In the past, I’ve thrown a slider and it’s been a pretty effective strike-out pitch for me. I threw it one day in the fall with some good results, but my coaches told me afterwards that they didn’t want me throwing it anymore because they said they really like my curve and that many times when a guy throws both pitches start to look slurvy and similar. I understand their concern, but there are many times when i’m on the mound and wish i was able to use the slider. My curve is a good pitch, and I catch guys looking with it, but it’s not a swing and miss pitch. I’m gonna talk to my coach about putting it back in my repetoir, but I was just curious as to what y’all thought about throwing both the slider and the curve.