This would be a matter of personal taste. I usually don't bother wasting skill points on getting new roles or skills, but that doesn't mean I wouldn't, if the circumstance arose.

When I was in the lower levels, I once got a youth striker who was very fast learner. He leapt from 4* to almost 6 in the first season. Because he was gaining points at such a fast rate, I started adding them to learn another role (AMR). It took less than two weeks for him to achieve the points. Now there are rarely any ST who have a second role, so when the time came for him to leave (after 7 seasons), the transfer auction went mad, and I eventually got more than 3 times what he was valued at on a bidding war that went over 50 rounds.