Is a basal body thermometer more accurate then all other thermometers? if yes, why don't we ALWAYS use them?

Answer 1

The basal isn't more accurate, it is more precise as it measures temps in .01 degree increments instead of the regular .02 degrees. The reasons not to always use it are simple:
1. expense (this thermometer is more expensive)
2. time (must give a full 5 minutes to register for accuracy)
3. irrelevant (a fever is a fever, the difference .01 degrees makes is minuscule)

The reason for a basal thermometer in trying to conceive is because a regular thermometer isn't sensitive enough to pick up the minute body temperature changes that occur during ovulation.
(I'm an R.N. and battled infertility for 9 years)