Opportunity Cost
Tying up your money in Bitcoin during a prolonged dip can mean missing out on other investments that perform better during the time of the dip because one can use the capital used in buying in the dip to invest in other areas such as stocks, real estate etc so buying in the dip can make one to miss other investment prospects when the price is not up early
Are you for real buddy, is there any good investment setting currently better than getting some good amount of Bitcoin if you're lucky to find a good dip? Investing into Bitcoin during the dip isn't tying up your money since Bitcoin is designated for long term investment, on the contrary finding a good dip and lump summing on it is a blessing.
This point of yours is wrong Catching a Falling Knife
Dips can turn into deeper declines not all dips recover on the short term there are some dips that falls dip before recovering so buying in the dip is like catching a falling knife which could be dangerous trying to time the bottom can lead to multiple mistimed entries and larger losses without a solid strategy you could buy too early and suffer bigger setbacks
Now this is your main problem and you literally don't understand Bitcoin investment, Bitcoin investment it's shared for long term to get good profits, the price history validates it. Those that are really very profitable today are the long-term holders. If you want a short term activity, then you can fit as a trader
Dips May Not Always Recover
Bitcoin price can remain low for as much time as possible or even experience a longer time period It's important to be aware that not all dips are followed by a recovery and that there is no guarantee of future performance examples was when the price of Bitcoin fell from $20,000 in 2017 to $3,000 in 2018 a dip that lasted over a year which affected alot of investors which where only concerned about catching in on the short price fall to make some gain if you buy the dip too early you might be stuck for a months or even a years as the case may be depending on how long the dip may last.
At least in the past 15 years, Bitcoin has proven that dips always recover and the price goes soaring again and even strains ATHs during bull run, a thousand example is this period when Bitcoin had hit $119k+ ATH after having several dips before now