Strongly disagree. In fact, it's usually counterproductive to save your Smites exclusively for a crit. It's usually best to get the sure damage in an early round, preferably the first. And getting sure damage means you have to boost your to-hit stat. The only case in which I would save Smites for crits would be if a spellcaster ally leads off with a Hold Person/Monster ... and to get THOSE crits you actually do have to hit naturally, hence the need for to-hit stat in that case.
But in any event, I'll be just fine dealing 22.5 damage less than I "could've" in that crucial first round, over dealing the max potential damage in a round when the fight is more or less already won.