If the glyph is moved 10 feet from where it is placed, the glyph ends.
One big problem is this line from the spell:
"If the surface or object is moved more than 10 feet from where you cast this spell, the glyph is broken, and the spell ends without being triggered."
This isn't a big issue. It's a restriction. Think "kill zone prep".
It takes time and gold to place several Glyphs that are both offensive, defensive, and/or self healing.
Another restriction is in the spells prepared versus slots available. For example, a 6th level Valor Bard has 3 slots for Glyph of Warding that would be restricted to the target rules, 1st and 2nd level spells the Bard has, and most likely be planned for the following day.
An 18th level Bard can do the same with a combination 13 slots available for Glyph of Warding and Spell Glyphs plus 7 more slots that can only be Spell Glyphs. 10 hours of spellcasting and 2000+ GP of powdered diamond can be done with that day of prep for that planned location.
Picking up Hex or Hunter's Mark via feat and the kill zone can use an 8th and 9th level slot for a Power Word Stun Spell Glyph, a 6th and 7th level slot for CME upcast as a Spell Glyph, two 4th level slots for a Fount of Moonlight Spell Glyph, and a 3rd and 1st level spell slot for a Hex Spell Glyph.
Day of encounter the target in the kill zone takes a PW Stun and Hex, and the Bard triggers both Fount of Moonlight and CME buffs with a full complement of spells available. Shapechange into a Hydra for 5 attacks and 5 reactions. That's 5d10+25+5d6+10d6+30d8 damage in attacks before reactions while it lasts.
It takes an hour and 200gp to slip a qualifying spell in to a mix of damage with a Spell Glyph. It's not a stretch with a little prep time to bypass the concentration requirements on one spell.
There's room for shenanigans.