I think what it means in a practical sense is:
1) Unsurprisingly, they are choosing to operate as an over-the-cap team going forward
2) They are conceptually willing to go into luxury tax in a material way (otherwise, not worth giving up even the small assets they did to get the TPE)
3) Hollinger points out that this is likely most useful next summer, when they will be $25 mil from the tax line.
They may not use all the exceptions they have, especially if you consider Horford's semi-expiring deal (because of lower guaranteed money next year) effectively one as well, but it is quite nice to have that $17 mil one available for the next year.