After reading the most recent reviews, I almost didn't install the extension. However, I figured, if I install it and it doesn't work, I'll just remove it. But, if I give it a try and it does work, I've gained a tool that will fit my needs.

I'm happy to say that I installed the extension and it does in fact work. I'm running Firefox 93.0 (64 bit) on a desktop computer that's only a year old with Windows 10 Home for an OS. I downloaded Eno ver. 3.6.1

I will admit, I can see why some may have had difficulties in using the extension. It seems to have an issue with signing in to a Capital One account directly from the Eno extension. However, here's what I found to work for me. I log in to my Capital One account first through the Capital One home page (as I would if I was going to check account transactions for example.) Once I'm signed in, I then click on the Eno extension icon in the upper right hand corner of the Firefox browser. Eno will usually recognize my account at that point. From there, I go to the merchant of choice, navigate to where I would enter my credit card info, click on the Eno icon if it's not already open, then click "Use". Eno guides me through creating a new virtual number like it's supposed to. No issues.

If my Captial One account times out on it's own, Eno is also logged out of my account. This is by design and keeps my account secure. However, attempting to log back in to Eno can be finicky. Here's 2 work-arounds that consistently work for me. Right-click on the Eno icon and select "Manage Extension." Disable Eno by clicking on the little toggle switch. Then re-enable. If that doesn't work, disable Eno again and close the browser. Now re-open browser. Log in to your Capital One account next before enabling Eno. After you're logged in, enable Eno from the Add-ons Manager in Firefox (if the Add-ons Manager tab is not already open, click on the "More" button which is 3 horizontal lines in the upper right corner, then click on "Add-ons and themes").

To reiterate, I have found these 3 basic procedures to be very helpful:
1. Sign in to your Capital One account first before attempting to use Eno.
2. Know how to disable and re-enable Eno. Use as needed.
3. Close browser and then re-start browser as needed.

I also noted that some reviewers expressed difficulty with the Eno extension slowing down internet browsing. I have not experienced that yet. However, disabling the extension can be done easily when it's not needed to speed things up if necessary.

I feel that this extension is worthwhile to try downloading and using. The extension is pretty intuitive. The settings are simple and clear. The extension will walk you through the process of creating a virtual card number in just a couple steps. Eno even automatically adds the card number in the appropriate field on some sites. If it doesn't add it automatically, just left-click the copy icon next to the virtual number and then right-click in the card number field on the merchant site and click "paste."

Another nice feature is that when you create a virtual card number, you can set a time limit on how long that number will be active.

I'm quite happy I took the leap and gave it a try. I don't always like to try new things as there's a learning curve and I often don't feel I have the time. However, dealing with a fraudulent charge on a credit card also takes time (this happened to me recently.) Since the virtual card feature has the potential to protect my main account and physical card number, the little bit of time it takes to use Eno is worth the time it saves in the long run.