Take a look at bond futures prices: 1) unadjusted and 2) back adjusted. Take a look at a bond index: 1) price only 2) with coupons reinvested. Take a look at a bond mutual fund: 1) price only and 2) with coupons reinvested.
This will tell you where bond returns come from when you operate a constant maturity scheme.
Ask yourself: where do bond returns come from given the operation of a constant maturity scheme?
Do bond returns come mostly from price movement? Do bond returns come mostly from coupon? If the former then investment in a bond fund is a disaster in an era of rising rates. If the latter then you may come to a different conclusion.