I think the sense of the word professional here is not as a boolean professional/amateur, but the sense of professionalism, the characteristic of taking business seriously, not letting personal matters intervene, and in this case, investing into tools.

To put an example, suppose you hire a painter, and they show up with non-work attire, no ladder, no brush, they ask you to buy a can of paint for them and a brush. Compared to a contractor that bills you flat and brins their own ladder, has work clothing and shoes, an air pneumatic spray painter, a breathing mask. Who is more professional?

It's part of a broader debate for sure, OP seems to have done it more for the experience than to actually save 1.50$.

It always depends on results. It can be unprofessional to design a system that takes an external variable like S3 for granted, especially if it's not needed. As long as the hack isn't worse than the official $1.50 happy-path, you might as well save the end-customer a monthly fee and reduce your attack surface.

I think hacks like these have a positive effect on the industry. It pushes back on meaningless, encroaching monetization and encourages Conatbo to reevaluate their service offerings to ensure they justify the price.