The SMS Service Add on Subscribtion is a good Idea, but it might can be improved as following:
1.) The way this product add-on is being priced is not a good fit for smaller hotels. Why can't there be pure pay-as-you go model, maybe with a higher individual SMS charges, but only on the acutal volume sent? I mean, the cary over that remains from the 50 € each month for us cannot ever be consumed...
2.) Track clicks: currenty there is no way to know if the sent sms messages are actually improving online check-in rates. It would be great to have some sort of analytics to get some insight if the money spent is actually worth it (are people really clicking the link in the SMS and are the completing the online Check in ?)
3.) Allow to send individual messages from the guest profile, for example to inform guests without email about late check in procedures
4.) WhatsApp/Signal/Messenger Integration? If a guest is available on WhatsApp/Signal/any other DM Chat, use that instead, save SMS cost and use officially verified and registered WhatsApp for Busines sending telephone numbers for more trusted messages. Maybe start with Whatsapp integration only for it's popularity