While there certainly could be unsophisticated bots that only do HTTP only, it's incredibly easy to make ones that do HTTPS (especially with all the frameworks that exist today). And with most of the internet being HTTPS these days, most newer bots are likely to handle this.
You are right - it could cut it down a little. I just wouldn't expect it to make a vast difference. But it certainly wouldn't hurt and would be a good idea.






