I think part of the original idea was that giving them stats would help players still struggling to clear content before the next expansion's release get that little extra boost that would make a difference.
Otherwise, they could be just cosmetic items locked behind a long grind and it wouldn't make a difference to most players.
For some players, getting 6000 Causality is a long grind. No one is getting that many with a snap of their fingers.
It obviously isn't a long grind for those players who have the luxury of playing multiple hours every day, but they can turn it into a long grind by getting every weapon for every job.
But what grinds in the past were truly unique to the relics as opposed to not running the content for other reasons? Eureka is about as close as it would get though some might have still be doing it for the lore. But still players had reasons for doing it other than the relics.
Out of all the relics series we've had, only ARR had content that would be considered unique to the relic - the Chimera and Hydra trials. There was simply no reason to do either of those trials unless you were on the corresponding relic quest or helping someone else who was. There are players who don't realize those trials even exist because they've never done the relics. Even the mysterious maps, content added for the relic grind, ended up with another use (ask any hunter who blows their poetics on them trying to spawn Agrippa).
All the rest have been based around content that already existed for other reasons. Eureka and Bozja had their own reasons for existing; SE chose to also use them for the relics of their respective expansions. Eureka was very much forced in that you could not progress a relic without being in Eureka. Bozja wasn't - most players did most of the relic outside of Bozja because it was more efficient compared to fighting drop RNG until SE fixed that late in the expansion.
Many of the past relic steps screamed "pay for your upgrade with your tomestones" even if it wasn't all of them. Yet the things we would be asked to do would have also generated tomestones in addition to the drop items or the Light we were trying to collect.
All SE really did this expansion was cut down on the double dipping with the relics. We had to make a choice between using the tomestones we got for doing the content for the relic or for other uses instead of getting an item drop and having the tomestones to buy those other things.
Someone who does Savage raiding wouldn't feel the difference because they probably don't use the tomestones for anything.
Then there's someone like me who doesn't do Savage. Do I use the tomestones to complete the relic stage, do I buy catch up gear for alt jobs I rarely play, do I buy craftings materials, do I buy Rains to upgrade the crafted gear? Using the tomestones on the relic means I now have to do more content if I also need those tomestones for gear (whether crafted or purchased) for alt jobs. That starts feeling grindy indeed.
How many players were panicking because they expected to find cheap crafted gear on the marketboard when a relic patch dropped just to find prices skyrocketing because instead of buying crafting mats with tomestones, players were buying relic upgrades?
It's a good example of Your Mileage May Vary depending on what you include in your game play and what part the tomestones play in the first place.