I love bit-banging, sometimes you want to go that route even if the uC does have specialized hardware. I remember having to bit-bang I2C on multiple occasions because the standards are so loose.. good times.
Recently I had to bitbang I2C through a voltage level translating buffer that had a direction setting pin that needed to be manipulated when sampling SDA on input. The uC's hardware I2C block obviously couldn't handle that extra signaling oddity. Not the fastest approach but then this I2C application wasn't that high speed to begin with. Good times indeed!
... and often the specialised hw doesn't go far enough. ie- i2c and spi hw that doesn't have enough buffering to be left on its own. Either we babysit the interface or we can leave it to do its own thing until we get an interrupt for completion. Do a halfway job on the hw and we revert to the babysit case. Not bitter, just ranting.