A back light is impossible on this type of opaque display (most LCDs are not opaque). So it would ned to be a front light. But, really, it needs to be seen to be believed — I really never think it should have a lit screen. Compared to devices that really did need screen illumination — such as the 1st gen Game Boy Advance, WonderSwan or Neo Geo Pocket — the Playdate is using screen technology that is decades newer and far, far better.
And the 1-bit is a real vibe, personally it takes me back to classic Macintosh. I find it quite liberating to not have to think of colour, at least at this point a few years into Playdate development.