I don't think this is specific to chat; pretty much the same question could be asked about any SaaS offering. At the end of the day, rolling your own is at leas

I don't think this is specific to chat; pretty much the same question could be asked about any SaaS offering. At the end of the day, rolling your own is at least somewhat of a risk in terms of how much it will cost, how soon it will be ready, the quality of the product being made by your employees who potentially aren't experts in the given domain, etc. In the ideal case, it would probably cost a lot less than paying for service, but you need to weight that by how confident you are in your ability to achieve that, and sometimes a high cost with a known upper bound is going to be more palatable than an unknown cost that's hopefully lower but potentially unbounded.