Of course it matters....
If your building micro niche sites, and you want to rank for small easy to rank keywords.... do you want to target keywords that have 10s thousands of competitors all targeting the same keyword(s) as you?
As soon as you reach on page x ... there are 10 or 40 other sites that over takes your places coz they are also targeting the same keyword. Then your stuck in a long fight.
Just my $0.02
I'm not saying that a low competing page result count can't correlate to low competition, it can.
I'm saying that it's not always the case that a lower page count means lower competition and therefore isn't reliable. Plus, there are much more solid ways to determine competition strength so there's no point in using this metric.
Back in the old days when there was nothing but allintitle and PR it was a better metric (although still not as good as looking at the PR of the top results). But these days when you've got tools like Open Site Explorer and Majestic SEO which do complex analysis, there's no reason not to check the top ranking sites and throw allintitle into the trash.
Here's one quick example. I had to use the second result for these terms because Open Site Explorer didn't have info on both of the first results.
allintitle: cats - 23,500,000 results
allintitle: weight loss - 17,000,000 results
Second result for "cats"
www.cats.org.uk
PR6
Page Authority: 66
External Followed Links: 4,776
Total Linking Root Domains: 779
AdWords Aprox CPC: $1.25 (US Exact Match)
Second result for "weight loss"
en.wikipedia.org/wiki/Weight_loss
PR6
Page Authority: 76
External Followed Links: 14,141
Total Linking Root Domains: 1,674
AdWords Aprox CPC: $5.03 (US Exact Match)
Looking at just the result count, it would appear to be a good bit easier to rank for "weight loss" than "cats". Even looking at the PR of the first result looks as though they would be somewhat even.
But the Open Site Explorer data suggests it's harder to rank for "weight loss" and the fact that people are paying over 4 times more to bid on "weight loss" in AdWords than on "cats" strongly suggests that "weight loss" is a more lucrative keyword and would therefore invite stronger competition in the SERPS.
This is just one example of course but it shows that looking at result counts can be misleading and that there are much better metrics to use.