Call and Put Options Payment

“Notice the difference between the arguments for call options and those for put options: call option holders pay the strike price (and can benefit from holding the option and paying later) whereas put option owners receive the strike price (and can benefit from exercising the option and investing the proceeds at the risk-free rate)”

What does the author mean by “Paying Later”. When you buy a call option you have already paid the option premium. What am I missing??

I guess it’s paying the strike price later when the call is exercised.

by ‘paying later’, the author likely means to delay exercise of the call option.

the Call you bought only gives you the right to buy the underlying at the agreed strike price. depending on conditions, it may be better to exercise immediately if possible, or wait and exercise at a later time. This is true for both Calls and Puts (Calls are generally better off exercised later unless there is a significant loss due to lost dividends)
edit: and of course, it is possible that you are better off not exercising the option at all and instead let it expire.