Arsenal had no money to spend in Winter because of inflated contracts that Ivan and Arsene both gave away like free candy. Getting rid of all that nonsense including players like Mustafi, Ozil, El Neny, Jenkinson, Koscienly, Ramsey, and Welbeck should all help in structuring the club's finances better for the future. I would hope that Xhaka is hopefully added to the out list, but I can't see it due to how much Emery has played him this year.
CL is super-ultra-mega important for Arsenal to get into, some of those automatic funds can give us a bit of a buffer and open the ability to spend some legit money this summer (more than Chelsea who's getting transfer ban). Of course on the other side this will all take time and this season wasn't going to be bump-free either. None of Wenger's teams were built over night as well.