My view is based on the way I look at the functions and roles in an organisation. Within a technology organisation, whatever the size, whatever the budget, you will have certain roles that need filling. The priority and amount of time needed by each of these roles will however depend on stage, size, budget etc.
An example is a UX designer. I would argue that any customer facing business needs some UX design, they may not be able to afford it and they may not need very much of their time (depending on the scope of the requirements) but UX is a core competency in any modern website.
A generalist front end designer will probably be good enough for many occasions but given the choice, most companies would prefer a specialist as that will improve customer experience and conversions.
Likewise, an early stage or small business may not be able to jusify a CTO full time or even part time, but they will need some CTO thinking in their business.
A CTO is not a developer. That is a different role.
A CTO is by definition a 'C' level role. This usually means a role that is ether on or reports into the board. A CTO therefore needs to be making the big decisions, thinking strategically, ensuring a company can scale. In bigger businesses they may recommend acquisitions.
A small or new business doesn't need this type of person full time, but on the other hand it's not a good idea to hire a developer and call them a CTO. You can see from my examples above, they are very different roles.
Going back to the central point of this article. A CTO should not be coding because they're too busy doing C level duties. If you're good at wearing multiple hats then a smaller business could have their CTO heavily involved in the development work as perhaps a team leader or architect.
In this role they might be pair programming, reviewing code etc but I'd recommend that they avoid writing production code as this could cause a major distraction to the CTO part of their job. Likewise a CTO could take on the product owner or product manager role, again this includes a risk that the person may be too distracted by the cool product geeking.
As an interim measure, this kind of multi hat wearing can work well, in the long run it can become problematic. Don't you always want a specialist doing the work for you if you can get them?