Giving control to your leads is never a good idea.
Throughout your sales process you should make your leads feel like they are in control, but should never really give up control.
Sending a Calendly link to your leads means giving them the power to schedule a call with you whenever they want and even forget about it (that happens).
I have observed that the best way to go about scheduling a call is to propose a date and time while asking for their email address.
Curious, do you use a Calendly Link?