Sentence Correction

since it is primarily prescriptions
here what does 'it' refer to

IMO:

it = that benefit that is attracting customers and making them buy more health related items

'It' while used in the start of the sentence refers to what follows it. The prior sentence with the wrong use of the word it, is what probably causes the confusion coz clearly it does not reflect prescriptions and drugstores which are plural words. That should be the red flag.

Wongee, you're right. The second it refers concisely to the main attraction of the pharmacy.