You mentioned that tips are a different asset class than bonds. Can you explain why that is?

Well, the simple explanation is that equities are, for most intents and purposes, inflation adjusted.
Other than those rare moments that inflation is so high that the economy breaks, smoothed earnings are fully adjusted for inflation for the typical firm.
The downside is that the prices are very volatile with no fixed endpoint, and future earnings and value are hard to predict for individual securities.
You know inflation won't eat you and you'll do fine over the very long haul on average with diversification, but everything else is an unknown.

Bonds have a very specific end date and value, and coupon, removing a lot of those unknowns.
There is default and currency and jurisdiction risk, all of which are relatively comparable to equities, so that's kind of a wash.
But the big variable is inflation, which is utterly unknown, and very much overlooked by people looking at the longer term.
Buying a bond is like making a huge wager that inflation will NOT take off. Who wants to take that bet?

Inflation protected bonds are different from either of those.
Government ones don't have default risk, just currency risk. (Corporate ones exist too, but they're pretty rare)
The main thing is that they include a fixed coupon like a normal bond, but a real one with no inflation risk...a combination that doesn't exist in either of the two above.

Basically, it's the only asset class for which you know in advance how much you'll make.
That's worth a lot.
(except for currency risk, which most people either don't think about or are happy to take on)

The only thing more useful would be an inflation-protected coupon stream (pension) that is guaranteed to last for life and has no default risk.
Which kind of exists...most people don't value their government cheques nearly as highly as they should.
Put it this way: if you wanted what it provided but from a private source, what would you pay for it?

Jim