Given the parameters baked into the auto-boost functionality (XFR, PBO) are typically the same ones you'd be working with for manual overclocking, you're not likely to gain much.
As an example, my 2700X at stock can do 4.1GHz all-cores, easily. A few cores will do 4.3GHz as needed (the max turbo, out of the box).
To actually sustain 4.3GHz across the board, stable, the voltage required is beyond what I would consider 'safe' for 24/7 use.
In my situation, I'd need excessive voltage for +200MHz. For most workloads, the performance gain is pretty minimal.
For bragging rights & just because you can... Manually tuning is the way to go.