Hello @Doubleo,
Your understanding there is correct. You can have more than the number of supported profiles/contacts within your Klaviyo account; however you would primarily be limited to your plan’s number of supported profile/contacts within your campaign sends.
To add to the great details that @alex.hong already provided the use of “people” and ”profiles” are synonymous with each other and mean the same thing. Each contact/person you have in your Klaviyo account will have a “profile” within Klaviyo. This means that from the screenshot example provided, the $60 a month plan would limit you to a maximum of 2,500 recipients within a single campaign; even if you had 5,000 profiles within your Klaviyo account. I would also suggest taking a look at the Understanding Who Is in Your Account Help Center Article to further understand how profiles/contacts are accumulated within your account.
Also, when you attempt to send a campaign whose recipient count surpasses your plan limit, Klaviyo will actually prevent your campaign from sending and display a warning message during the final step of the campaign creation during the schedule/send section. Klaviyo’s warning message will indicate that you do not have a plan to sufficiently sent to these recipients and prompt you to upgrade your account to increase your plan’s threshold prior to sending.
I hope this helps!
David