Activation or rental: which number do you need?
The choice comes down to one question: will this account ever ask you to verify again? If yes, you need a number you still have when it does.
Activation numbers
One service, one code, a short receiving window, and the cheapest price available. Ideal for a sign-up you will never revisit, a trial, or a throwaway account.
The limitation is absolute: when the window closes the number is gone, and with it any ability to recover that account.
Rental numbers
Yours for days or months, accepting messages from any service. More expensive per number, far cheaper than repeatedly verifying the same account, and the only sensible option where the number is the account's login.
A rough rule
Messaging apps, payment services, marketplaces with payouts, and anything holding value: rental. One-off sign-ups, trials, and content you would not mind losing: activation.
