BPSK bandwidth for symbols not integer wavelengths
The examples in the textbook are chosen for clarity. They will have like what, a 2:1 ratio between carrier and data frequency? In practice this may be 10 000:1 or more. And even with the carrier being an exact multiple you can't be sure of the phase; chances that zero crossings of carrier and data coincide are slim.   

You need a higher bandwidth to get the sudden changes in level right, but if you have 10 000 carrier sines for 1 bit you don't care about that distortion in the first sine.  

I wouldn't worry about it.