There are a couple of advantages of liquidity in a GIC ladder that may not apply to you, so you have to make the call if it's important or not.Is that enough liquidity it probably doesn't matter if maturity only comes around once a year?
First advantage would be a quicker ability to re-invest cash thrown off your account that you want to go to fixed income. If you have to wait a year for a rung of a ladder to come due, what do you do with cash until that time. A six month ladder offers that cash a home quicker and the ability to enjoy the 5 year rates (which usually are greater than short term).
Second advantage is for those that need the cash during decumulation. Easier to get at your capital every 6 months rather than wait a year.
A third difference that may be an advantage or disadvantage is that if rates are rising you'll pick up the higher rates of the day twice as fast. But that can work against you in a dropping rate environment.
These advantages may or may not apply to you. The multi rung ladder was just a suggestion to your dilemma, but you have to work it into your situation.