Yes, it is better to take depreciation most of the time, but not quite as much as you imply. Keep in mind the rules of depreciation in Canada:
Depreciation on rental properties reduces your rental income, but cannot create or increase a rental loss - so in years where you may lack tenants for some months and have less income, you may not be able to take much or any depreciation.
You cannot 'double-up' on untaken depreciation in future years. You have the ability to claim depreciation up to the fixed level for all combined assets you have in the same depreciation class. So pausing depreciation can't allow future 'catchup'. From a theoretical finance standpoint, if you had this rental property for 20+ years, pausing that tax-refund cash inflow for 1 year is nearly the same as eliminating it forever, given diminishing returns of the time value of money.
Taking depreciation [or, 'Capital Cost Allowance' for Canadian tax purposes] does not reduce the 'Adjusted Cost Basis' of an asset for capital gain purposes; instead it reduces the 'undepreciated capital cost' of that asset. When you sell the property down the road, if it is for more than your original purchase price [net other adjustments], you will pay the same capital gain amount regardless of how much depreciation ('CCA') you took. So, this does not 'convert' fully-allowed deductions into half-taxable capital gains.
When you sell your rental property, you will take additional income in that future year called 'recapture', which is basically the sum total of all historical depreciation taken, up to either the original price or the final sale price.
example: assume you buy a $150k house [and let's assume $50k of the value is in non-depreciable land, and $100k is allowed for the 4% depreciation on buildings], and you claim $2k depreciation in year one [1/2 depreciation in the first year], and 3,920 in year 2 [98k remaining * .04], and 3,763 in year three. This is 9,683 total reduction of income across 3 years. In year 4, if you sold for $200k you would take back the full 9,683 depreciation as 'recapture'. If you sold for $145k [let's assume $50k value in the land still, and $95k value in the building], you would take recapture of just 4,683 - reflecting that you sold the building for 5k less than you purchased, but had taken total depreciation of 9,683.
So in summary, as you state, depreciation taken today is an immediate reduction in your income, however you should be aware that there will be a pending 'hammer drop' of recapture income in the future when you sell.
If your marginal tax rate stays the same every year, it is a no-brainer - take every deduction as soon as you can. However if your marginal rate will go up (and stay up!) in the future, it may be worthwhile to hold back on taking full depreciation now, to reduce the impact of recapture income in the future.
Even if your marginal tax rate will be higher in the year that you face recapture [likely, given you will have recapture income, + possible capital gain from the sale], assuming it is far enough in the future, it can still be worthwhile to take CCA. Whether this would be exactly true for you, would depend on precise calculations.
Example: Assume you have a rental property with a simple 10k annual depreciation available to you, and you are in a 35% tax bracket today, and will be in a 40% tax bracket in 5 years, when you will sell your property for a gain. Assume your tax refund would otherwise be invested in a stock portfolio earning 10% return. 4 years of 10k deductions at 35% = 14k net savings the first 4 years, and 40k of income at 45% = 16k extra tax in year 5. However the 10% compounded earnings on the earlier deductions is itself worth about 4k combined, leaving a net benefit of taking the depreciation of 2k. HOWEVER! If you earn less on your investments, or sell more quickly, or move into an even higher tax bracket, things can become less clear - for example with the above numbers, if you move into a 45% tax bracket in year 5, your net benefit of 10% annual investment compounding almost exactly breaks even with the extra tax costs in year 5. It can be hard to tell the future so some doubt can exist here, but annually projecting these things for yourself can help you make the decision each year.