alt Hacker NewsSSD1306 is a bit in the middle. It's technically a 128x64 monochrome bitmapped display, but it's organized as eight 128x8 "rows", with each byte representing a single 1x8 group of pixels. That organization really favors being treated as either four or eight lines of text - trying to use it as a generic bitmap display gets awkward, because it's only addressable at the level of those 1x8 groups.
ST7735 is more of a standard (color) bitmap display.
SSD1306 is just 1KByte for a second buffer, so even a rather low-end MCU likely can spare that. And you'd absolutely just draw normal lines if you use a display like that.
It's very easy to use it as a generic bitmap display, there's nothing awkward about packing 8pixels into 1 byte, and you can set the addressing mode (horizontal/vertial) to whatever you want, etc.