If you do not want to use them, disable them. If you disable them, no updates will be done (and existing ones will be deleted).
You cannot delete them, physically, because they are on /system partition, which is read only. That means, even if you would delete them as root, you would not get more space for another apps or your data. However, the read-only /system has more functions, that you would lose: it has known file layout (so you can image-update your phone, if you ever get an update), it is signed (so you can know your phone has not been tampered with, as it is not going re-sign itself once modified), it is also for factory-reset/sofware recovery purposes, so once you wipe /data, your phone will be in factory-mint condition (software-wise, of course).
Most of the time the disable button is greyed out and cannot be clicked.
I'm not familiar with the /system partition but it seems logical that if I can delete them as root, it means I can also install something else in its place or put some of my data there, which would help me a lot as my phone does not allow for an additional SD card.
Whether it is disabled or not, depends on the phone vendor. In the phones that I have currently available (Google, Sony, Samsung), all the Google applications can be disabled. Samsung usually prevents disabling their applications, but still allows disabling Google ones.
If your vendor prevents disabling the apps, you can still try the route using adb and pm (google for adb pm disable).
The point I was making about /system is, that you don't want to mess with it, even if you have root. You can break more than you think, including dm-verity, and then you are not going to boot anymore. Also, apps installed in /system are getting updates installed into /data, so it is not going to solve your problems with space anyway. You would have to repartition your phone, which on ARM platforms opens a new can of worms (partitions are defined in the secondary boot loader, which is signed too. Moreover, if you do this wrong, you get a brick, you are not going to boot without reflashing the original SPL in an external programmer).
You cannot delete them, physically, because they are on /system partition, which is read only. That means, even if you would delete them as root, you would not get more space for another apps or your data. However, the read-only /system has more functions, that you would lose: it has known file layout (so you can image-update your phone, if you ever get an update), it is signed (so you can know your phone has not been tampered with, as it is not going re-sign itself once modified), it is also for factory-reset/sofware recovery purposes, so once you wipe /data, your phone will be in factory-mint condition (software-wise, of course).