College teaching is unique as a profession. Job security and advancement (i.e., promotion and tenure) are largely determined by the excellence of performance of tasks other than the one the person was hired to do (i.e., teach). Such tasks include publishing, securing extramural funding (grant writing), and being willing to function as a team member, including doing a fair share of committee work and advising (collegiality).
While teaching well, by itself, is unlikely to yield job security and advancement for an assistant professor, a failure to teach well (e.g., receiving low teacher ratings from students) can reduce the likelihood of achieving both, unless he or she by the end of the probationary period has developed a strong national reputation as a scholar (through publications) and/or has generated a great deal of extramural grant funding. At the very least, it is highly likely to keep him or her from being awarded promotion and tenure before the “up or out” year. During my 30-plus years in academia, there was rarely a case in my college of someone who didn’t have excellent teacher ratings being awarded promotion and tenure before the end of their probationary period. The few exceptions were persons who had generated a great deal of extramural funding and/or had exceptional publication records.
While teaching well, by itself, is unlikely to yield job security and advancement, not doing so is likely to make it more difficult to achieve both. Therefore, unless you’re willing to risk your future on becoming a publishing and/or extramural funding superstar, you’d be wise to invest in becoming at least an adequate teacher, because doing so reduces the likelihood of your perishing (i.e., being terminated by the end of your probationary period). Furthermore, unless it’s a “turn-on” for you to be hated by students, teaching well can make your job more enjoyable!