Not worth it.
For rehab work you can use some other form of bench or even just your regular sturdy table and a band (see first vid below).
KB ballistics & SLDLs, barbell deadlift variations, oly lifts and some squat variations (like low-bar backsquats) will cover everything you need for the posterior chain. You can even include bodyweight stuff like natural glute-ham raises (see second vid, note: these are super hard even for accomplished lifters).
Even if you only use some of the things I listed, it will leave no gaps in your PC development (strength, power & hypertrophy).
Bodyweight is for free.
A good barbell with weights will cost you 700-1000$ (new), but you will have countless of different exercises you can use it for.
For 1000$ you also get a full set of high quality KBs (8-48Kg in 4Kg steps) and just like with the barbell you can use it for a lot of other exercises.
Now to get to the reverse hyper machine. These things cost 500+$ (Rogue 800$, Westside from 950$ to almost 3500$
), but you can only use them for reverse hypers (and maybe 1 or 2 special movements, that nobody really does anyway).
So ask yourself do you want to buy a tool that's only good for one specific exercise when for the same price you could get one or multiple other tools that can be used for countless exercises.
Even if you already got the other tools wouldn't it be better to use the money for something else? For example a weekend city trip with your girlfriend/wife, buying a new set of winter tires, going to a SFG/SFL/SFB one-day course or even saving more money and attend a SFG/SFL/SFB cert?
