Both let you earn from hosting. They suit different situations.
AFFILIATE
The customer is ours. They hold the account, pay us, and contact us for support. You earn a one-off commission per referral. No cost, no risk, no work beyond the referral. No control over pricing, branding or the customer relationship.
Best for: bloggers, content creators, and designers who refer occasionally and do not want to be involved afterwards.
RESELLER
The customer is yours. They hold an account you created, pay you, and contact you for support. You set your own prices and keep the margin continuously. You pay us for the reseller package and carry the risk. You handle all client support, which is real ongoing work.
Best for: designers and agencies hosting multiple client sites, and anyone building a hosting business.
CHOOSING
If you refer a handful of people a year and do not want support calls, affiliate. If you already maintain client sites and answer their questions anyway, reseller, because you are doing the work regardless and may as well hold the margin.
You can do both.