The most restrictive thing about this to me is the pinout. Only 6 I/Os really limits the applications in terms of SerDes / parallel-to-serial applications as well as in terms of configurable pinout, which is (IMO) where small programmable logic really shines. In my experience microcontrollers are cheaper and easier for pretty much any kind of the simple serial/processing stuff you could handle with such a small logic device.
In my opinion 1K LUTs is fine for a lot of cool applications - I built an ((E)EP)ROM / RAM simulator out of an iCEBlink40HX1K board to use in programming and reversing old ECUs. It works great and is vastly superior to the old school method of doing this (hardware dual port SRAM) since the pinout is configurable on the fly.
In my opinion 1K LUTs is fine for a lot of cool applications - I built an ((E)EP)ROM / RAM simulator out of an iCEBlink40HX1K board to use in programming and reversing old ECUs. It works great and is vastly superior to the old school method of doing this (hardware dual port SRAM) since the pinout is configurable on the fly.