If there is any valid criticism of the Paris accords, it's that they aren't stringent or BINDING. Which is the exact opposite of Trump's complaints about them. By the very nature of them being non-binding, they don't impose anything on the US.
Just that fact almost entirely undermines whatever Trump said.
In addition, however, new coal is already more expensive than renewables, which are getting cheaper at a rapid pace. However, more importantly, it's significantly more expensive than natural gas. The odds that the US would build a coal plant are minuscule (and even if someone did, assuming that somehow coal got cheaper than natural gas, the amount of money saved over building a natural gas plant instead would be meaningless).
I would have thought a master dealmaker like Trump would know that giving up something you weren't gonna do anyways in exchange for anything is a good deal.
But finally, none of this matters, because Donald Trump could have continued to do whatever he wanted (build coal plants, increase US emissions, etc.) without the Paris accords imposing any sort of mechanism to stop him from doing it.
What this shows is that the US cannot be trusted to stick to even a promise as toothless as the Paris accords. Combined with the lack of reaffirmation of Article 5 in NATO, the only real effect this will have is diminish the US's standing among its allies.
The Paris Accords were largely symbolism but important nonetheless in bringing everyone to the table, and showing a way forward and showing that climate change is something all countries need to handle and worry about. Donald Trump's act is also symbolism showing that the US doesn't care about agreements and pacts and that Climate change is not something they really believe in.
Btw, both Chinese and Indian governments have targets that are much more stringent than what they agreed upon through these accords, and both are well ahead of even those more stringent targets.