Several honest reasons. Some women have a history or condition that makes HRT inappropriate; some weigh the risk-benefit picture and personally prefer not to; some have symptoms that are mild enough not to warrant it; and some simply want to understand the alternatives before deciding.
HRT being the most effective option for hot flashes - which it is - does not make it the only legitimate one, and a good clinician will discuss the alternatives rather than treating HRT as all-or-nothing. If you have not yet mapped the HRT side of the ledger, the pros and cons of HRT is the starting point.

