What's the problem with having unmanaged switches hanging on your network?

I'm sure I'm asking for an ass-kicking with this question.. but I'm still learning.

I have several Dell N3048 switches on my company's LAN which servers and workstations connect to properly, etc. However, we have one building with a very tiny training room with 10 or so thin clients crammed together and very limited network jacks in this building... my solution (so far) is to use an unmanaged TP-Link gigabit ethernet switch to connect the thin clients to and then this switch also connects back to the building's managed switch.

Is this a problem at all? If so, can someone help educate me?