It's neat that they've added a Qwiic-compatible connector. I've been impressed with how many Qwiic peripherals Sparkfun has released, so I'm glad to see it getting more traction.
On the other hand, it is a really convenient standard connector.
On the other hand, I2C means you can only have one of each kind of device due to address clashes, the lack of an interrupt pin is quite limiting, I2C is too slow for things like displays, and 3V3 isn't really enough to power LEDs like WS2812Bs.
To be clear, it's not just a matter of power, but it really is the voltage: shorter wavelength LEDs use semiconductor materials with bigger bandgaps https://en.wikipedia.org/wiki/Light-emitting_diode_physics#M...
What I don't like is that the connector is a nightmare to hand solder and isn't as strong as some. But then, I suppose that's what breakout boards are for.
There's a few other use cases that can't be done easily in a modular way unfortunately, mostly to do with power. SPI needs more pins, and there's no way to handle 12v, and only one module can be supplying power.
Stuff is not quite fully plug and play yet although it would be super cool.