"More valuable" would suggest age and contract are in play here, which would favor White with his more attractive deal and younger age. I don't think anyone would dispute that. I will, however, offer some positive words regarding Holiday since this post seems to be suggesting he might be overrated or considered a mild disappointment.
Holiday is a more versatile defender than White. He can more capably guard 1-5 compared to White, because he's bigger and stronger. White can be overpowered in the paint whereas Holiday can hold his own against some of the strongest players in the league. White is more of an nonstop energy guy, able to keep in front or at least pursue and contest from behind. However, he's not as physical as Holiday and he doesn't really disrupt ballhandlers in the same way. I think that's why White has never been great at creating steals, whereas historically that's been a strong suit of Holiday's.
In terms of rebounds, Holiday is also much better, showing a knack for running into the scrum and plucking the ball out of the air or using his body to control space. That might be the best way to describe Holiday's impact as a defender compared to White. I think White is an indefatigable on-ball defender, but he doesn't really "control space" the way Holiday does. When you're facing Holiday, you kind of have to always be aware of where he is and wary of running the action into his "sphere of influence." I just don't think White controls the area where he's residing the way Holiday does, and that makes a huge difference.
On offense, White clearly seems like a better complimentary/off-ball player. However, that's a very different responsibility than being the second option on a team like Holiday has had to do in his career. Holiday has played on teams where he's had to consistently score, while White has had the luxury of not having that burden. Could White average 20ppg? Sure, he has the talent but it's not clear he has the mentality. I think that there's value in Holiday having that experience over someone who has never really had to do it consistently in White.
Holiday is a slower, more methodical player who seems more comfortable throwing his weight around in the paint, whereas White is faster and will try to blow by guys and work his floaters and flip shots. Sometimes, you do need that energy from a White because we already have other guys that sometimes play too slow (Tatum). It does also seem like White is a faster decision-maker compared to Holiday, though some of that could be familiarity with the team. White seems like a better spot shooter, but considering Holiday has been pretty efficient himself the past three years, I wonder if Holiday will eventually start shooting it a little better.
In conclusion, they're both really good players but I just wanted to offer some defense of Holiday over White. There are a lot of things Holiday brings to the table that White isn't really great at.