I am pretty practical when it comes to these things.
If you are good at something, never do it for free.Doing so will only devalue everything you do and represent and that kind of behaviour and thinking will be very hard to get rid of and hold you back for a very long time.
Regarding the topic of having opinions compensated, one must note that this isn't anything new either. We live in times where corporations pay huge amounts of money and try to cheat the systems in many a way in order to get informations about people, their preferences etc.
Google and Facebook being the more prominent examples, but also things like reviewing apps that compensate you with all sorts of percs do qualify here.
The thing with steemit is that it takes a different approach, one that I particulary enjoy as far as I can tell.