Outside of the case you cited it doesn't look like there has been any material impact from this convention. This doesn't make it useless however, this is something that many would argue is useful to have codified.
There is also an important tidbit hiding in article 12 of the convention:
States Parties may not refuse a request for mutual legal assistance on the ground of bank secrecy.
This is huge for states like Switzerland, which have an infamous history of bank secrecy. This opens up possibilities for investigators pulling the thread of terrorist finance.
Keep in mind though, addressing terrorist financing with legislation is bound to be relatively unsuccessful. If a state is supporting an insurgency/terrorists - either explicitly by financing them (as Russia has been accused of) or implicitly by turning a blind eye to their operations in the state (as Qatar has been accused of) - it is unlikely to be cooperative in addressing concerns from the international community and in the case of explicit support will have covered its tracks. Non-state actors financing terror are likely using black money in the first place, so the source of the financing is well upstream from the terrorists and is already a different and hard-to-address legal concern.
In general though, it is hard to argue with the precedent of "Don't Fund Terrorists", and this convention opens a door for greater inter-state law enforcement cooperation when it comes to tracking down and shutting down the financing of terrorism.