Retail towels are usually less durable and come with lower GSM ( between 250 GSM to 450 GSM)
Hotel towels are subject to more washes and hence need to be more sturdy to withstand the Washes on almost daily basis
As such the best Hotel Towels are made of double piles to give the strength to towels and also Higher GSM to withstand the wearing of Fabric from frequent washing. The GSM ranges from 500 to 600 or even 650.
GSM increases the weight of towels and hence higher GSM towels cost more.