When I download something using torrent though, the speed is shown as 10 MB/s
You forgot the i, qBittorrent displays speeds in MiB/s not MB/s.
Mb/s = Megabit per second
MB/s = Megabyte per second
MiB/s = Mebibyte per second
Anyway 10 MiB/s is ~ 83 Mb/s so you're fine, seems you are already hitting your max speed.
OP is confused but I'm pretty sure they are right about that part. Most (all?) ISPs advertise service in Megabit / Gigabit speeds. Definitely here in the U.S. not sure if other countries do that differently.
Also most speedtest sites measure in Megabit / Gigabit. e.g. https://www.speedtest.net/ is a popular one and by default it measures bandwidth speeds in Megabit / Gigabit.