To the extent that high inflation is harmful for growth and welfare, a central bank that continuously tries to give short run positive surprises will entrench long run high inflation, which will be bad for growth. BIS central bankers’ speeches  3  and non-traded food are inflating merrily to push up CPI.
And then it takes time before people actually buy more electric cars. These time lags often prevent fiscal policy from providing the necessary stimulus at the time it is needed, and not when the recovery is already well underway. And even if fiscal policy were not subject to any lags, governments would still face the issue of coming up with the right fiscal package.