Don't freak out . . .
Maybe you should, hmm . . . .
On the one hand:
The only commercial inductor-based RIAA units are long ago out of production.
On the other hand:
They were top-shelf studio gear, used in radio stations etc., or low-production semi-DIY products.
Anyway, doing an inductor-based RIAA is not a quick little hack-it-together DIY project (trust me, I know a little about being a hack.) However, as Dave says, it is one step closer to audio nirvana for some. I've heard one and it definitely put the technology onto my list of things to try when I have the time & focus.
Anyway, to try and answer your original question:
The "big idea" behind an inductive EQ circuit is that it presents a constant load impedance to whatever is driving the EQ circuit. Other implementations of RIAA equalization present a HUGELY varying load impedance to the driving circuit. So this is an advantage for the inductor based EQ circuit.
Unfortunately, this constant impedance is usually quite low - 600 ohms - in the classical implementation (based on the TANGO inductor which is itself based on a Pultec product from about 50 years ago.)
This presents a problem - hard to drive well - along with its advantage - constant load impedance.
Some of the egghead audio DIYers have thought about scaling the impedance up to say, 6K, or 10K, to try and get the best of both worlds. This has proven hard to implement in practice - the theory of the inductors has been tricky to match in reality.
Other attempts have been made to build more robust drivers that will not be compromised unduly by the 600 ohm load. I have heard one of these (Thomas Mayer's implementation of 2000, since upgraded I think?) and it was well worth the effort on his part since I didn't have to do it, I just had to listen
Sounded like pure sweetness. Very true, effortless, and rich.
Hope I haven't added any layers of confusion and even maybe stripped a few away. It's not a simple question by any means but the answer is worth pursuing for sure.
-j
