Seem to be two strands of thought here....
1 - should PPLs practice basic instrument flying skills regularly to get out trouble when necessary
2 - is the IMC rating a good rating for a PPL to hold
I'd say that number 1 is pretty much a no brainer. Yes.
Remember that (a minimum amount of) instrument appreciation is taught on the PPL for this reason. There is nothing to stop you adding to this by receiving further instruction and keeping reasonably current on basic manouevres such as a 180 to get out of IMC into VMC. As others have said, its easy to be caught out - at what stage does heavy haze become IMC and how gradual is the transition?
It's easy to fly into light cloud that was difficult to see through the haze, flying into the sun - it all looks a bit milky! If you panic due to lack of familiarity with the panel, things will become dangerous and luck will be a major factor in whether you live to tell the tale.
Number 2 must come down to a personal decision. I don't hold an IMC rating (although I have a night rating) because I have no intention of flying in marginal VMC. If something develops quickly, I'll divert and get the train home.
Now that is easy for me as (a) I have a share in an under utilised aeroplane - so no 'get hom itis' pressure, (b) I have a working lifestyle that allows me some flexibility and (c) I don't wish to push the envelope in this direction as my flying is purely recreational and what I can do now is more than enough to give me a lot of pleasure.
Of course everyone will have their own view/choice and that's exactly as it should be.