Interesting information here.
I have no first hand experience on FLS, but on the system that Airbus essentially copied and improved upon, Boeings IAN. IAN has quite a few advantages in my view, it gives a pseudo ILS indication so it can be used with or without FD allowing "raw data" flying on any kind of (straight in) approach, there is no procedural change from precision approaches like ILS or GLS to non precision approaches like overlay or RNP (non AR) approaches as long as they are straight in. Everything is flown in approach mode instead of LNAV/VNAV or VORLOC VS. The big downside for IAN is that it is not temperature corrected and that non-straight in approaches have to be flown using LNAV/VNAV, which is still fully managed but not using ILS procedures, which does include RNP AR approaches.
From what i read above FLS seems to have the same restriction on being usable on straight in approaches only, but is temperature corrected, which is a huge improvement in my view. Now, if airbus would only implement a 5 and 2,5NM range mode and vertical situation display on the A320, but sadly, it would also need to implement quite a bit bigger screens for that.