Yes of course there are many reasons why DCAing strategy is not same like lum sum, DCA strategy makes you to invest low amount on Bitcoin so with tim you can accumulate enough figures of Bitcoin.
With lum sum you won't be able to accumulate Bitcoin frequently, when I made a plan to buy Bitcoin I didn't get to know that I have to make sure it doesn't affect my expenses life.
Like DCAing makes you invest and you have to not let the accumulation process not affect your expenses.
Another good thing about DCA, it has a lot of advantages. aside from what you said of which is that it won't affect your budget as you can allocate small funds to your investment over time. DCA allows you to buy Bitcoin at different amounts over time, which might not be possible if you purchase it in a lump sum. Some investors may not have enough money if Bitcoin's price suddenly drops when they have invested all their money at once.
And I can also add that DCA simply completely ignores short-term volatility, so for people who are more emotionally sensitive and not used to the extreme volatility of bitcoin, this will always be the best form of investment.
The average price of an asset that only appreciates over time is always the most interesting and intelligent strategy. It makes the investor's life lighter and mentally healthier.