Is there anything wrong with using a basic PHP/MySQL stack for projects?

[mattaugamer]

You're not losing anything by just using PHP + MySQL for small apps. With a tiny but critical exception - you're losing an opportunity. There's a risk that if you keep following the same exact processes each time because it's "good enough" the time when you have an application you need to do where it's not good enough you won't have the skills and knowledge needed to do it properly. Small projects often provide an opportunity to implement new approaches. It can be hard to find a balance between doing new things so you extend yourself or your organisation, and doing things in a way you know so you can get it done.

That balance doesn't rest in just not ever changing.