I'm thinking of purchasing an Apple 2TB Time Capsule - ME177AM/A that I could use wired or not with my MacBook. Is this a suitable device?
Frankly speaking, no. There are several different reasons for this.
The Time Capsule was designed to store backups using Time Machine on your Mac. In general, you would not want to store any "active" or "working" files on the Time Capsule since it was not designed for this type of application.
Even if things might seem to "work", you will have to figure out how to back up the files that are present on the Time Capsule, since it cannot back itself up.
The Time Capsule......which was originally designed more than 5 years ago......was officially discontinued by Apple in April 2018. To say that the product was "long in the tooth" would be a very polite way of stating things.
The Time Capsule also holds the distinction.....in my opinion......of being Apple's single most unreliable product. So, users who use the product as it was intended......to store back ups.....very often have a second backup strategy in place as well.
The simplest solution.....which is also almost always the most reliable solution.......would be to simply add a USB drive to your Mac and store your folders, graphics, fonts, etc there. But, don't forget that you will still need to back up both your Mac and USB drive.....which is a task that a Time Capsule could likely handle if you really are interested in a Time Capsule.
Another possible solution would be to use a dedicated NAS (Network Attached Storage) device, like Synology......which can both store your files and also back them up to another drive installed in the NAS. I'm not using a Synology NAS at this time, but will be using one again soon.
Perhaps some of the other Synology users will post to offer their recommendations on this product.