Should you handcuff in fantasy football?
There is no right or wrong answer.
There are examples where handcuffing paid off, such as owners who drafted both Dalvin Cook and Alexander Mattison of the Vikings in 2021 and were rewarded with 3 elite performances from Mattison when Cook missed time. However, there are also plenty of situations where it didn't pay off -- like if you selected Hassan Haskins in 2022 as Derrick Henry's handcuff, and he contributed very little, even in the one game that he was the clear replacement when Henry was out.
Ultimately, handcuffing is fantasy football's version of insurance. You "buy" it to protect your investment, yet you hope that you don't have to use it. (In the example above, you drafted Haskins while hoping that Derrick Henry would get every carry for the Titans all season long.) The cost is a draft pick and a roster spot that could otherwise be used on a player that could make an immediate contribution or at least be a viable bye week replacement.
Most likely if you are in a league with limited bench spots, handcuffing will not be a useful strategy because every roster spot is so valuable that you can't afford to hold a player who likely will not be useful most weeks. If you have a deeper bench then you can afford to roster that type of player. Or if you're in a larger league with 14+ teams then the quality of players may be stretched thin enough that getting a "handcuff" may be a better option than the other players available.