Performance Reviews were definitely not a waste of time and a very important carrot that motivated the company. they were great when things were going well and my startup was growing, but when we started to have churn and laid off half of the company they were less important. They were even less important when we had another round of layoffs after that. I would send very mixed signals at an annual review if I couldn't give anyone a raise and couldn't offer them a way up the corporate ladder, even for top performers. E.g., "You're doing awesome work but all we can do is let you keep your job." Furthermore, equity grants would have been meaningless. I had multiple employees say tell me they didn't think the stock was worth anything, since the odds of an exit had dwindled. Growth had stalled, so they cared purely about salary and career path. I spent a lot of 1x1s talking about what they wanted to do after working for me and helped them plan it out and make progress towards a new goal.

Having worked at several well funded startups and mentored or been involved with many more through founder friends around the accelerator in town, I completely agree. Especially at the early stage startups just don't have time for these formalities. Regular 1:1s are pretty much the best option.