Probably the senior Devs that believe in Bubble the most are those that started pre-funding, while Bubble was still bootstrapped. Nothing says true believer like an early adopter who is still building with bubble today.
And I might just dare to say, a level up is the early adopter who started as non-technical, as they needed to truly believe in bubble to start as a non-technical person as everything technical was new to them.
One up from there are those who started to learn a thing or two about more technical things like custom CSS, JavaScript , database structuring, APIs etc, due to their experiences with Bubble.