Combat versatility
Having access to multiple arts and forms of combat can give our hypothetical person multiple avenues in battle.
On one hand, our man would not be defenseless in battle if he were to lose his sword - he can still cast things like shield spells or a blinding spell to try and regain an edge.
On the other hand, he wouldn't be completely defenseless if his magical energy (mana) was drained.
Spells may be used tactically in order to confuse an unaware enemy, and does provide a quick way of changing the combat strategy.
Preserving magical energy/mana
If a sorcerer's energy is rather finite, knowing swordsmanship or other forms of armed combat can help the sorcerer to save on his magical energy. While a simple spell like throwing a fireball might cost little energy per fireball - if the battle were to drag on, even simple spells like fireballs could wind up losing our sorceror a lot of energy.
In short, the sorcerer can then rely on using "regular" forms of combat in order to preserve his mana reserves.
There is an additional thing that the sorcerer can use - his sword and gear can provide material for transmutation spells - instead of having to summon "bound" weapons, he can leverage the existing material in his already physical weapons and won't have to maintain the shape and function of a bound/ghost/ethereal weapon.
Weapons (and other gear) as vessels
The sorceror may have the possibility to leverage his weapons and gear as additional reserves of mana, or may have the option of enchanting them for added power in combat.
Especially if the sorcerer/magic user is somewhat weaker than his peers, or has limitations on use of magical energy - using swordfighting and other regular combat techniques can aid a lot in healing the user to save energy/mana, especially if the battle wears on over a long time.
In this context, the user does have a big advantage in having two energy resources to tap on: Mana for spells and incantations, as well as physical prowess and stamina for regular combat. 227