Pros and cons of painting cinder block in basement?
pros - looks better, smoother surface that makes less dust

cons - seals the surface up well which prevents moisture from evaporating from the block.  if its 100% sealed on the outside, it wont be an issue, but if you have any moisture, it will trap it in the block.

painting block is an extremely common commercial/industrial finish process.  the trick is to use the right approach and material.  

step 1 - fill and seal with concrete prep coat.  this material is usually sprayed or put on with a texture gun, but if you want you could probably do it by roller (i wouldnt bother, just spray it)

https://www.dulux.ca/pro/products/masonry-coatings/perma-crete-ltc-concrete-block-and-masonry-surface

step 2 - paint over with whatever you want

omit the sealer and you can count on 10 coats minimum to seal it up properly.