It is “better” only in terms of the sign value, since Jesus offered the first Communion under both forms. Thus we most fully observe the manner of the first Communion by partaking in both forms: the Host and the chalice. Nevertheless, the full sacrament, the whole Christ, is received even if only the Host or the Precious Blood is consumed.
There may be good reasons one cannot or should not partake of the common chalice such as health, struggles with alcoholism and the like. Parishes, too, may have good reason to limit the offering of the chalice due to a lack of time, a lack of an adequate number of ministers, concerns for spillage, etc. Further, some with celiac disease often partake only from the chalice. In either case, and under either form, the whole Christ is received.