I think, firstly, that spending 15s trying the CTRL-c approach is a worthwhile tradeoff. If you don't find anything, then sure, spend another 30m - 60m setting up perf, KDAB, etc. Maybe more if you're on an embedded device.
Secondly, the author seems to say that he's used this on embedded devices with no output but a serial line for the debugger. This is also a 15s effort[1].
It's basically a very low effort task, takes seconds to determine if it worked or not, and if it doesn't work you've only lost a few seconds.
[1] I'm assuming that if you're developing on a device supporting a serial GDB connection, you've already got the debugger working.
Furthermore, note how your reasoning is quite different from what the website you linked to says - it basically says "there are no good tools" (which is untrue) whereas you are saying "manual GDB sampling might be good enough and is easier to setup than a good tool" (which is certainly true).
but they all support gdb
I'm not debating that manual GDB sampling has its place and value. I'm debating that perf is "lying" or that it's impossible to get hold of off-CPU samples, or profiling of multithreaded code in general.