These appear to be more often prescribed by non-dermatologists for the treatment of seborrheic dermatitis (source). This is likely due to a poor understanding of cutaneous fungal disease.
When compared to antifungal solutions, the effectiveness of hydrocortisone cream appears to be only marginally better (source). However, potential issues exist with prolonged use of hydrocortisone, mainly development of atrophy or telangiectasia (dilation of the capillaries) (source). However, some studies suggest that their relative danger is rather small and has been blown out of proportion (source). Regardless of this, seborrheic dermatitis is believed to be a long term condition, and thus, corticosteroids are likely not the best option.
Overall though, corticosteroids are effective for quickly getting rid of seborrheic dermatitis symptoms. However, issues tend to quickly return after application is stopped (based on communications with readers).