Personally, I see access to FIP Coupons as the real privilege. Using the Coupons, travelling across Germany on an ICE, on some obscure narrow gauge rack railway in Switzerland, hopping on and off suburban SNCB loco hauled services to get around Brussels or taking an SNCF RER service to some French backwater, for FREE, feels special. Getting to chat to local staff, getting a knowing nod (or alternatively having to explain the 48hr boxes...


), feeling part of something bigger, really feels special.
With the UK stuff, free travel on the TOC/Group varies depending on your group, but can't argue with that. Personally I don't really use the privilege of free travel on my own TOC for leisure as it's too much like being at work, plus I really enjoy driving. I travelled by train locally far more before I worked on the railway. I'd say the most special aspect of UK Priv is being able to go on the Snowdonia Mountain Railway for something like £8, bargain! (Unlike the heritage railways, I felt no guilt as the SMR is clearly a primarily commercial operation.)
With the 75% off, I don't wish to seem unappreciative of it, as it is worth having and I'm sure many would love it, but it leaves me a bit cold. The situation is far better now than it was when it could only be applied to full Open fares, and it's helpful to have the flexibility of turn up and go 75% discount (though with seat reservations now on IC TOCs, that's a moot point), but, my personal feeling is that public fares are overpriced, as such, it feels like we're paying the fare that the public should be paying! And in many cases the public are actually paying something equivalent, as I travel mainly off peak, when Advance fares aren't too dissimilar to the Priv fares.
I'd love to have Boxes, it would suit my occasional travel habits far better, but it's far from a being a hill I'd choose to die on. If anything, a change I'd suggest is allowing Standard Priv pass holders to purchase First Class fares. I'd be more likely to travel by rail now on modern stock if I could go in First without hassle and it'd be generating more revenue for the railway than would be the case otherwise. Might also help fill some seats in the post Covid/business travel era...
On the other hand you wouldn't expect a person who works at M&S to get free shopping or even discounts at Sainsburys or Aldi...
Though I always say to that, do M&S staff also sell Sainsburys or Aldi products or offer them instead of M&S products if they might suit the customer better? The rail industry is different. For example, there are some booking office staff who rarely actually sell their own TOC's 'product'.