Vendor / Platform Viability - If you shut down or deprecate your platform (looking at you google!) - I loose my application. Product Limitations - I have no other option besides re-write if you choose not to support something I need after I start using your platform. Are you investing enough to support me in the future? One of the reasons many GUI web editors let you get to the code, is that it provides an escape hatch if the included tools don't work and you need to fix a problem right now. Financials - What happens if you (or whoever acquires you) decide to do an Atlassian / Oracle and let me know my next renewal is 400% higher? Processes / procedures / options - By limiting things like code access you make it harder to find ways to fit weird corporate or regulatory requirements. I might be required to keep every version of my application's code for 7 years. You might make your platform hold the last 60 version of each file. I can't guarantee my auditors that I have every version of the code.
As such I would be hesitant to do anything too significant in a No Code platform. On the other hand if the application is of minor significance (i.e. can easily be re-written) or temporary it would be acceptable.
However the value of that code will vary by language. If your doing the magic in a very niche language then it will have less value then if it uses one of the mainstream 10 or so languages. Additionally if the code depends on services that are only offered by your platform, then again it will have reduced value as the lock-in is still there.
Depending on strategy (especially around monetization) code exporting may not be viable for your platform, and the workarounds would take too long / too much resources. Now what that means is the tool needs to be SO GOOD at whatever niche it fits that it is a no brainer for me to put my concerns to the side and just try it if I need to work in that area. If your tool lets people save a heap / make money quickly while keeping quality up, it will speak a lot louder then the voice of reason worrying about long term supportability.