It really depends on the product, company, and possible regulations.
If it's 'just' a restaurant website that has a bit dynamic content, and you can make reservations. I think it's much better not to build/host your 'own' backend, but just use services. If you have a payment platform, and it needs to be cost efficient and to apply to a lot of regulations, you need your 'own' backend, and you need to think hard about the services you use.
It really depends on the product, company, and possible regulations.
If it's 'just' a restaurant website that has a bit dynamic content, and you can make reservations. I think it's much better not to build/host your 'own' backend, but just use services. If you have a payment platform, and it needs to be cost efficient and to apply to a lot of regulations, you need your 'own' backend, and you need to think hard about the services you use.
The "build or buy?" question would be the next step, I think.
But you made good points to that question!