Given our financial situation transfers like that make sense.
We need more transfers like the Suso one. Sign a talented but struggling player for little or no money and make him into a highly useful player, who theoretically could be sold for >30m and make good, much needed, profit for the club.
Nonetheless more often than not those former "wonderkids" flop, so i wouldn't have all too much hope. If all you needed to do is to sign former wonderkids to improve the team/make big profits, everyone would do it. You need to pick the right one's and give them enough playing time to develop. Not sure if that will happen with Halilovic, probably not, but definitely worth a try.