I agree. This is why I slowed down tremendously on the amount of ACL shops I do. But mainly because my goal is profit and not just a free meal. I used to do like 10-15 of these shops a month. But then I realized I'm coughing out so much out of pocket expenses that just sit an accrue interest on my credit card. (I always use my credit card for out of pocket expenses for mystery shopping). Anyways even if I spend under the reimbursement, I still used my gas and time and like I said I accrue interest on what I spent so by the time I get the actual payment I have to pay my credit card off for the interest that acrrued while waiting for the payment.
Even if I used a debit card, I still wouldn't do as many ACL shops. There's no fee, so no point to me. Like @walesmaven said I would maybe just include it in a route if I was hungry or something. I would also do it if I needed to take someone out for a birthday or something. That way its no out of pocket for me. So yes there are reasons I will still work with ACL just not as consistently as before.
I think if you're shopping for free meals than ACL is for you. But if you need profit, I don't think there's much of a benefit. I'm also gonna try what @HonnyBrown said and start asking for bonuses on shops that sit there for weeks.