The Monterey Bay is ideal for IFR training.
There are multiple IFR airports within minutes of Watsonville.
All of this leads to effective IFR training, with little time wasted for travel.
The Monterey Bay is frequently subject to coastal fog and this provides an ideal introduction to 'actual' instrument weather conditions.
This is very important experience during training that is often missed in desert training locations, where there is little 'actual' IFR training experience.