Anonymous comments have a complicated form - and people don't want to comment. They have to select certain pictures, related to a subject. When using a mobile template, they don't see all the buttons needed - and there are many steps until you finally publish a comment.This blog owner would prefer Blogger commenting, before 2015, when anonymous comments meant unending waves of spam.
Could is be simpler? With no checking pictures, with just typing few numbers, or without any security question at all?
Blogger made the anonymous commenting sequence intentionally complicated, to cut down on the volume of spam published using anonymous commenting.
The non optional CAPTCHA reduces spam volume, so blog owners can moderate.
By cutting down on the spam volume, they made it possible for many blog owners to actually moderate Blogger hosted anonymous comments. This allows everybody to work together, and make the spam filters more accurate - and makes Blogger hosted comments more useful for genuine blog guests, and blog owners.
Before they added the non optional CAPTCHA, many blog owners simply could not use anonymous commenting. Moderating all of the spam, to find a few actual comments, took too much of everybody's time.
The mobile template, on mobile computers, complicates CAPTCHA use.
Using mobile computers, and the special "mobile template", will be painful for some people. Mobile computer displays involve a series of compromises - and the non optional CAPTCHA form shows the weaknesses of the compromises.
Removing the non optional CAPTCHA would make life easier - for spammers.
Removing the anonymous comments CAPTCHA would make it possible for spammers to enjoy use of mobile computer templates. Spammers would not be limited by mobile computer displays - and they would, once again, abuse anonymous commenting mercilessly.
Life would be so much simpler, without the spammers. Unfortunately, spam cannot be eliminated - it can only be suppressed.
But you may suggest improvements, to Blogger, if you wish.
All that said, if you think that the anonymous commenting process can be made easier, let Blogger know.