Thank you for your question. I personally believe in applying light moisturisers even for oily skin types, definitely so for combination skin types as well. Skin that is appropriately moisturised actually can normalise oil production. The key is finding an appropriate product to use.
Our skin keeps changing with age, so what works now may not work later on. For example, skin moisture decreases with age so good quality moisturisers or serums help a lot with that.
I don’t think not using moisturiser now will have long term ill effects on the skin. Neglecting your sunblock can result in that though, so remember to always reapply!
Hope this helps!