I doubt they'll add much value - they don't want to cannibalize their core business even more. They'll probably just add a button that says "talk to a UBS wealth manager" when your portfolio value crosses a certain threshold.
The one exception is alternative investments like real estate and private equity. Once you are HNW or at least high enough to have enough investable assets that you qualify, PE can be an attractive investment class that Wealthfront won’t touch.
Also, human advisors can manage, or at least access, investments across brokerages; that is, you don’t have to worry as much about wash sale rules and can do tax loss harvesting because they can see your sales elsewhere. I have to have TLH turned off on Wealthfront because it has no way of knowing about what things I’ve sold elsewhere.
Not financial advice, YMMV, etc.
I'm interested to see if UBS can add value in those ways you mentioned, while still using sophisticated automated strategies for cost savings purposes.
Also note that Vanguard, JPM, Schwab, Fidelity etc. are getting in the robo-advising/direct indexing game.