There are 2 problems:
1/ ESC will check battery voltage after connecting battery. If you use resistor, the voltage goes up slowly and ESC can see too low voltage, because it will start before completaly charged capacitors. If you use ESC with switch (ESC with switch, not timer separated with switch) then the processor starts when you switch it on, and you will do it only when battery is properly connected. If you do not have switch and ESC starts checking too early, and you still want to use resistor, then you must switch off battery checking by some setting which depends on ESC firmware ... exactly like guys from CC recommend. Slide switch on timer cannot affect this problem.
2/ ESC will beep after arming. ESCs usually check several things after start and if all is OK, then ESC arms itself and usually beeps after arming. One of those thing to test is also iddle signal from timer. So if you do not have switch, it will start already with battery connecter via resistor and beeping will make voltage drop and it will confuse ESC and push thim to low voltage regime. Slide switch on ESC will prevent this situation because it will allow all tests only when you switch it on with properly connected battery. If you have switch on timer wire, it will not allow making iddle signal and it will also prevent arming and beeping.
Well ... little longer answer, but as you see it is not so simple :- ))) All depends on firmware in ESC, but short answer YES is valid only for ESCs with switch (for example Jeti Spin). If you use switch on timer lead, then the answer is "it depends" and proper solution for CC is in Peters post (the question is if they know that we feed ESC with proper signal already connected with resistor). If you do not have any switch, then I do not recomment resistor without good testing.