It depends on the SAAS and what they are trying to do. Do you have an example?
If it revolves around:
1. Serving content
2. Selling things (on a small scale)
then wordpress would be a good platform. However if you're looking to build a SAAS that does more than that and requires custom models, interfacing with different technologies on the back end etc. then you're in for a world of hurt trying to conform wordpress. You're much better going with a framework like Laravel.
Wordpress is a good tool if your use case falls within the WP core or available plugin ecosystem.
If it revolves around:
1. Serving content
2. Selling things (on a small scale)
then wordpress would be a good platform. However if you're looking to build a SAAS that does more than that and requires custom models, interfacing with different technologies on the back end etc. then you're in for a world of hurt trying to conform wordpress. You're much better going with a framework like Laravel.
Wordpress is a good tool if your use case falls within the WP core or available plugin ecosystem.