DCA is effective in the process of averaging against volatility and putting purchases in an ordinary income stream, however, when you have a lump sum, it may be worthwhile to buy on the downside or buy more actively. It all depends on whether you have an effective plan and with a clear plan, you should not touch on monies that are likely to impact on your necessities. Basically, both strategies can be applied using the same capital, it is primarily a matter of timing, risk-taking, and disciplineness when using discretionary funds.
The discretionary income to be used depends on the level of your comfort and not even about the market environment and If you say buying on a Lump sum is worth while buying on the down side then to me you are describing buying the dip and not buying with the lump sum, because talking about buying with the lump sum has nothing to do with the market conditions but rather an investor decision to buy immediately with the available Lump sum amount irrespective of the market conditions,
You are right, however I believe that some people prefer not to invest all of their money at once without thinking about market conditions first. Sure, a lump sum means you invest everything all at once, but not everyone is comfortable with that.
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