Once we moved from 24 paychecks (semi-monthly) to 26 paychecks (bi-weekly) and a coworker said, "I like it. You get more checks." So? "So it's like you get paid more!" But you don't... bc your annual salary is still the same. "You get more checks and more often, so it just feels like you get paid more!" I swear she probably spent more too because of her perceived "fake raise". What a dumbass.
While the dollar amount per year may not change you are getting more money the more frequent the pay periods due to the time value of money. Ideally you would get paid per second (or whatever the smallest practical interval may be - daily perhaps) because then you can invest the money on your behalf as your are earning it instead of the employer using the money they owe you and investing it on their behalf (which they definitely do).
That said... yes your coworker is a dumbass if they are spending more money or think that they get a "bonus month" for the two months where they get 3 pay periods.
While technically true, this effect should be negligible. If you can prove me wrong, using a "typical" salary, then I'm all ears.
Also, more importantly, this benefit is only realized if you actually invest the money somehow. Considering how financially dumb these coworkers are, I'd be surprised if they actually invest it. Meaning they aren't realizing the time value of money. I suppose Mrs. Cool Cat is realizing it.
Oh and finally, because you want to bring up the what should be negligible effect of the time value of money for a biweekly vs semimonthly pay period, the 26 biweekly pay schedule works against you for taxes. Suppose you're $5000 above the 15% tax bracket on a 24 paycheck cycle, and you always get inflationary adjustments to your salary. You will always be $5000 above the 15% bracket. But suppose now you switch to a 26 paycheck cycle. Because 365 days is not divisible by 14 days/biweekly period, there will be a year with a 27 paycheck cycle every so often (let's just say it's every 5 years). Also suppose every paycheck is $3000 (whether this actually gets you into the 25% bracket is not the point of the exercise). So over a 5 year period, you will have paid a bit more in tax on the 26 paycheck cycle vs the 24 paycheck cycle because every 5th year you will be taxed at 25% on the last $8000 of your pay instead of the last $5000, even though you are getting paid at the same rate per hour every year.
EDIT: Had a math mistake, thought I originally typed $500 instead of $5000.