Yes, that’s right. In evolution, things evolve to meet a specific need. It has nothing to do with the fact that if a species that can’t fly happens to have a variation that causes it to be covered in feathers, that variation will continue to be passed on to future generations as long as it does not present such a disadvantage to survval as to mean that the organism will not survive to reproductive maturity. The dinosaur just says “Ooh! I say! It’s rather a trifle nippy. Could do with some insulation here,” and poof - as if by magic evolution provides.
No No No. One of the more important principles of evolution is that any adaptation within a species will continue if it doesn’t provide a selective disadvantage. Those feather’s may or may not have provided a selective advantage to that creature, but as long as it is able to stay alive until it matures sexually and can find a mate, it will pass the adaptation on. Over many successive generations the accumulation of other adaptations within its lineage may render its decendants unable to reproduce with members of the species that this feathery ancestor originated from. These decendants will be said to be a different species.
Sorry to sound so sarcastic and condescending, but I must nip this rival Lamark theory of evolution in the bud before it spreads. Lamark was gracious enough to prove his own theory wrong on his own and that’s where it should have ended.