Generally speaking you may be better off using an out-of-the-box solution as long as your requirements aren’t too customised, because the cost of building and then maintaining all the operational facets of a website can get burdensome over time. Not to mention PCI compliance and data security requirements etc. Could your booking time slots effectively be constructed as SKUs and then loaded into a standard platform like Shopify or Wix? Shopify probably scales better and can be extended further later on – but it really depends on your available budget and volume. Happy o chat further offline, if you like.