The bulbs versus switches argument has been going on since the very beginning of this forum, and there are passionate opinions on both sides.
The short answer is that each has their pros and cons, and you just have to look at each case.
(The argument about cutting power to the bulbs doesn’t really apply since there are several different ways to solve that problem. If you are in the US there are even devices which fit right over the top of an existing switch to give you wall control of the bulbs without actually cutting power to them. But that does mean adding an additional device which adds additional cost.)
Bulbs have their use cases but I struggle to think of many.
There are four main advantages to smart bulbs:
One) you can install them without needing to change any wiring, which is helpful for renters and any specific switch where there is no neutral at the switchbox
Two) you can get one that changes color or color temperature. Color is particularly useful for notifications, as you mentioned. Color temperature is a feature that a lot of people like, as you can go from cool white to warm white and back again at different times of the day or in different seasons.
Three) you can easily take them with you when you go to visit friends or relatives for overnight stays. I myself am quadriparetic, use a wheelchair with limited hand function. Being able to take a Hue starter kit and an echo.to my brother’s house when I visit is hugely helpful for all of us.
It’s also good for families with little kids who have trouble reaching the light switches. If the kids are used to voice controlled lights at home, taking the kit along to grandma’s again helps everybody. 
- if the light you were automating is a table lamp anyway, a smart Bulb is often easiest. ( there is a UK device for table lamps, the swiidter, but it requires splicing into the lamp cord and is not available in the US)
For some set ups, the switch will be cheaper. For others, a bulb will be cheaper. So that one depends on the details.
I’m not saying don’t get smart switches. If your overhead fixtures have multiple bulbs, the switch will most likely be less expensive than replacing all the bulbs. And most switches default to the off setting if the power is cut and then restored, which many people prefer. And the switches look exactly like conventional switches, which again, many people prefer.
All I’m saying is that sometimes a switch is the best choice and sometimes a bulb is the best choice and you can just look at it case-by-case. But as soon as you mention that you’re thinking about one or the other, in this forum you’re going to get multiple posts from people favoring each side as a general truth. It’s a never ending argument. 
If you’d like to read more about the wall switches that can be used with smart bulbs:
If you’d like to get the details of the bulbs versus switches discussions: