This 18.5% is mostly real staking / lending yield (~18.3% of it). Only about 1% comes from token emissions. It is single-asset, so there is no impermanent loss to drag you below holding. It can still fall, but it isn't a disappearing subsidy.
Real fee/staking yield: 18.3% · token emissions: 1% of the headline.
No impermanent loss here — the ~18.3% is real income on the very asset you'd be holding anyway. Only any emissions portion fades.
Source: DefiLlama. Verdict is a heuristic over public data, not financial advice.