Established altcoins keep repeating the same pattern relative to btc, which is readily readable, even when fiat prices tumble dramatically and by swing trading, you can redouble your position over time without risk.
This was not a good assumption as no once could figure out the exact bottom for any coin. Repeating same pattern is definitely short living one. If you buy by assuming a bottom then you may need to wait a prolong time when market shows another bottom. I have experienced this kind of wait with many coins even with bitcoin as well. Because, there will be no guarantee that every time market will bounce back after certain fall and there will be no limitation for any coin to have same bottom level. Making lower low is most common; in such scenario, your funds may get locked in.
There were plenty of examples where coins never bounced back and stayed at lower circuits; one good example is EOS (a coin after so-said huge successful ICO, lost more than 95% value and staying at lower circuit for more than 3 years).
So, swing trading may get you profits if you are lucky for not entering at the "last round" of pump and dump.
Swing trading through Dollar-Cost-Average may help you crack profits as this strategy includes your waiting time as well. No strategy without providing time for waiting may not work for profits all the times.