Is a suited 10 with a face card worth holding?
Yes — hold both. J♥ 10♥ is worth 0.5074 per coin on 9/6 Jacks or Better vs 0.4713 for the jack alone. The suited 10 is free royal equity.
The exact numbers — 10♥ J♥ 5♣ 8♦ 2♠
EVs are exact — every possible draw enumerated, not simulated — at max bet on 9/6 Jacks or Better. Check it yourself: the analyzer runs the same solver in your browser.
See all 32 holds of this hand ranked →Why
The ten costs nothing you were using — the other three cards are junk either way — and it buys a two-card royal, a straight-flush draw, and extra flush and straight chances on top of the jack's even-money pair. The suit is doing the work: the same jack with an unsuited ten is just a lone high card. One exception is worth memorising: with an ACE the ten stops paying its way. Solved on 10♥ A♥ 5♣ 8♦ 2♠, the lone ace is worth 0.4640 and A-10 suited only 0.4606, because A-10 makes no straight except the broadway.
Chart line #16 of 18 — 'Suited 10 + high card' — is written for 10-J, 10-Q and 10-K only, never 10-A. It is the last hold above lone high cards and a bare five-card draw. See the full solver-optimized strategy chart, or drill hands with exact-EV feedback until plays like this are automatic.