For me, it's because I love software. I'm also a perfectionist, I can mold software in all sorts of ways. Not so much with physical products.
What about you?
Way higher profit margin and better exit valuation.
You can technically not touch SaaS for a month or two and still have a basal amount of reliable passive income.
In other words, SaaS is a truer cash flow asset than ecommerce.
Ecommerce is highly transactional. I enjoy being able to build relationships, customize offerings for clients and get to know them.
Same reason: I want control :)
Control over the product experience?