I think you need to use your own sound judgement on this one. A poorly constructed sponsored post about an ICO can (dare I say will) come off as you giving your support behind that ICO. If that ICO was to go south - some might hold that against you. I am sure you would be able to word your post to maneuver around that issue, but it is something to keep in mind. I too am enjoying your posts about blockchain tokens. If you do go the sponsored route - I hope you don't forget about this series :)
Keep up the good work.